Select the option that represents the given sentence in the passive voice:

The reforms could have affected a large number of marginal workers.

The given sentence expresses a hypothetical scenario. The passive voice must also capture this essence. Option A states that the workers were affected (definitely) and hence can be ruled out.

Option C states that the workers affected the reforms, which is false. The reforms affected the workers and not the vice versa. Hence, we can eliminate option C as well.

Option D states that ‘a large number of workers can be affected by the reforms’. This sentence is the passive voice of ‘ the reforms can affect a large number of workers’, not the given sentence. Therefore, we can eliminate option D.

’A large number of marginal workers could have been affected by the reforms’ is the correct form and hence, option B is the right answer.