Change the following sentence into passive voice:
The students were solving the sums.
An action in a sentence can be represented in two ways, namely active and passive voice.
The passive voice always uses the past participle form of the main verb irrespective of any tense. Only the auxiliary verbs depend upon the sentence given in active voice.
The given sentence is in the active voice.
The correct answer is C) The sums were being solved by the students.
Option C) is correct as the subject of the given sentence comes in the place of the object and vice versa. Also, the main verb is used in the third form.
Options A, B, and D are not correct 'solving' should be transferred to 'being solved', the given sentence is not in the simple past tense, and 'been' cannot be used in the transformed sentence.