Change the following sentence into Passive form:

Someone has stolen the keys from my office.

The keys have been stolen from my office.

The correct answer is Option (4) → The keys have been stolen from my office.

Here's why:

• Subject change: In the original sentence, "someone" is the subject who performs the action ("stolen"). In passive voice, the subject becomes the object of the preposition "by" (which is often omitted), and the action ("stolen") becomes the main verb. Since the sentence doesn't specify the person who stole the keys, "by someone" is not included in the passive voice version.
• Verb tense: The original sentence uses present perfect tense ("has stolen"). In passive voice, the verb tense usually remains the same. Therefore, "have been stolen" is the appropriate choice.
• Object placement: The object ("keys") stays the same in both active and passive voice.

The other options are incorrect because:

• "From my office the keys were stolen" changes the sentence structure unnecessarily and is not as natural-sounding in passive voice.
• "My keys has been stolen from my office" is grammatically incorrect as "keys" is plural and requires a plural verb form ("have been").

Therefore, "The keys have been stolen from my office" effectively conveys the passive voice meaning while maintaining grammatical accuracy and natural flow.