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 correct answer is A)The political leaders were being interviewed by the reporter.
The option A is correct as the given sentence is in the active voice and to transform it into the passive active voice, the subject of the given sentence (the reporter) comes in the place of the object (the political leaders) and vice versa. Also, as the sentence is in the past continuous tense, the past participle form of the main verb (interview) is used after 'being'.
Options B, C, and D are wrong as the helping verb used (was) cannot be used here as the subject of the transformed sentence is plural, the sentence is not in the present continuous tense, and the helping verb and tense used is wrong.