Change the following sentence into the Active form.
It was believed that the secret formula had been stolen by a rival company.
Show answer & explanation
Correct answer: B
Explanation
The original sentence "It was believed that the secret formula had been stolen by a rival company" has two clauses. The main clause "It was believed" is in the passive voice, and the agent is an unspecified "people" or general consensus, which becomes the subject in the active form. The subordinate clause "that the secret formula had been stolen by a rival company" is also in the passive voice, but option B keeps this clause as is (in passive form within the subordinate clause), which is a correct way to form the overall active sentence.
Option A keeps the main clause in passive form within the subordinate clause of the new sentence, which doesn't fully activate the main idea.
Options C and D change the meaning or structure too significantly.