The correct answer is option 2. The sentence is incorrect because the tense of the sentence is wrong. The first option is incorrect because the tense of the sentence is present perfect continuous while the tense of the option is past perfect. The sentence is about earth’s revolution around the sun, a process that began millions of years ago and is still continuing, therefore, past perfect tense is not correct for the sentence because past perfect tense implies that the action occurred in the past and finished in the past, which we know is not true for earth’s revolution. Option 3 is incorrect as the verb ‘be’ is missing in the option. The correct option is 2 because it agrees with the tense of the sentence. ‘Has been revolving’ indicates that the tense is present perfect continuous denoting an action that began in the past but is continuing in the present. The tense of the sentence is also the same. Correct sentence: ‘The earth has been revolving round the sun since the beginning of time.’