Question

Select the most appropriate option for [3]:

• A. why was she sad
• B. why had she been sad
• C. why she was sad
• D. why she had been sad

Answer 1

The correct option is C why she was sad

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 be changed.
An interrogative sentence, when changed to reported speech, does not function as an interrogative anymore. It turns into a declarative sentence.
So, the word order of an interrogative changes to that of an assertive/declaratory sentence.
Option C: This sentence is the correct narration of the direct speech, as the question form 'are you' is changed to the declarative form 'was she'. 'Are' is changed to 'was' as the tense changes from simple present to simple past. Hence C is correct.
Option A is incorrect because the question form has not been changed; 'was she' must be changed to 'she was'.
Option B is incorrect because the sentence is in passive voice, in the past perfect continuous tense. But, the reported speech does not change its voice. Also, the sentence remains in interrogative form.
Similarly, option D is incorrect because the voice is changed to passive.
(When the direct speech is in simple present tense, the reported speech will change to its past equivalent, simple past tense. This applies to most other tenses.)