The radio towers have been tampered Basic rules to be followed for Ac
Right Answer is: B
Basic rules to be followed for Active/Passive conversions are:
1. The object of the active verb becomes the subject of the passive verb.
2. The finite form of the verb is changed (to be+ past participle).
3. The subject of the active sentence becomes the object of the passive sentence (or is dropped).
4. Preposition ‘by’ is used before object
The given sentence is of present perfect tense and it is in passive form. The structures for active/passive voices are:
Active: Subject + has/have + verb (IIIrd form) + object…
Passive: Object + has/have + been + verb (IIIrd form) + by + subject…
Someone is the correct pronoun here. Hence option B is the correct answer.