The correct option is A she had scored good marks
When a sentence is changed from direct to indirect speech, the subject
pronoun, verbs and tense forms also change. (This is because the speech is reported by someone else, and the tense
of the direct speech goes one tense back as it's spoken at a later time
now.) The meaning of the sentence
should not differ.
Option A: This sentence is the correct narration of the direct speech, as 'you have' is changed to 'she had' as the tense changes from
present perfect to past perfect.
('You've' is a contraction of 'you have' and the person changes from 'you' to 'she'.) Hence A is correct.
Option B is incorrect because the present tense verb 'have' has not been changed to past 'had'.
Option C is incorrect because the sentence is in passive voice, in the past
perfect continuous tense. But, the reported speech does not change its
voice.
Option D is incorrect because the subject in first person 'you' has not been changed. It should, as the speaker is a different person now.
(When
the direct speech is in present perfect tense, the reported speech will
change to its past equivalent, past perfect tense. This applies to most
other tenses.)