A prize will be given to whoever solves this problem.

Certainly, let's go through each option:

1. "A prize is being given to whoever solves this problem" - This option is in the passive voice and in the present continuous tense. It implies that the action of giving the prize is currently ongoing or in progress.

2. "A prize will be given to whoever solves this problem" - This option is in the passive voice and in the future tense. It suggests that the action of giving the prize will happen at some point in the future, once the problem is solved.

3. "A prize is given to whoever solves this problem" - This option is also in the passive voice, but it's in the present tense. It suggests a general truth or a habitual action, indicating that the prize is routinely given to anyone who solves the problem.

4. "A prize was being given to whoever solves this problem" - This option is in the passive voice and in the past continuous tense. It implies that at a certain point in the past, the action of giving the prize was ongoing.

Each option conveys a slightly different nuance in terms of the timing or context of the action, but all are passive voice constructions. However, the most appropriate option depends on the intended meaning and context of the sentence

Hence Option B is correct. 

Active Voice : - In the active voice, the sentence's subject performs the action on the action's target.

Passive Voice : - In the passive voice, the target of the action is the main focus, and the verb acts upon the subject.

Conversion  of Passive Voice Sentence into Active Voice For Simple Future Tense:

Rule used to identify that the sentence is in Passive Form with simple future tense is:

subject + will/shall + be + third form of verb + by + object.

For Example:

• Students will be taught by teachers. ( passive )

The subject is 'students', object is teachers and 'taught'  is the third form of the verb teach.'by' is used here according to the format.

While converting into Active Voice the rule will be :

subject + will/shall + first form of verb + object

In the question : -

1. A picture will be painted by Steve Jobs.

The active form of above sentence in simple future tense is : -

Steve Jobs will paint a picture . In this sentence , object (picture )  is converted into subject (Steve Jobs) and then ,  we use first form of verb (will) ,  and then the remaining part is the object (picture) .

2. The lesson will be learnt by John.

The active form of above sentence in simple future tense is : -

John will learn the lesson. In this sentence , object (the lesson) is converted into subject (john ) and then ,  we use first form of verb (will) and then the remaining part is the object (the lesson).

Thus , the Correct Option is B , 1.  Steve Jobs will paint a picture . 2. John will learn the lesson.

A new book will be published by the company next year.

Sure, let's break down each option:

1. "A new book will publish by the company next year" - This option is not in the passive voice. It's in the active voice because the subject of the sentence ("a new book") is performing the action of publishing, rather than receiving the action.

2. "A new book will be published by the company next year" - This option is in the passive voice. The subject ("a new book") is being acted upon by the verb ("will be published"), and the doer of the action (the company) is mentioned using the preposition "by."

3. "A new book would publish by the company next year" - This option is grammatically incorrect. "Would publish" is not a correct passive voice construction for this sentence. "Would" is used for hypothetical situations or conditional statements, not for expressing actions in the passive voice.

4. "A new book will have to publish by the company" - This option is also grammatically incorrect. It's not in the passive voice and the syntax is incorrect. It should be "A new book will have to be published by the company." However, this doesn't fit the original sentence structure provided.

So, the correct passive voice construction for the given sentence is: "A new book will be published by the company next year."

Hence Option B is Correct.