Reported or indirect speech is usually used to talk about the past, so we normally change the tense of the words spoken. We use reporting verbs like 'say', 'tell', 'ask', and we may use the word 'that' to introduce the reported words.
When the given sentence is changed to reported speech, the tense and pronoun will change. Also, an interrogative sentence in direct speech changes to a declarative sentence in reported speech, since the objective isn't to ask the question anymore, it is to report the speech.
Also, while reporting a question, the word 'if' is introduced.
Option A: The interrogative here has not been changed. Only the inverted commas (" ") and question mark (?) have been removed. This does not change the speech. Hence A is incorrect.
Option B: The speech is still in question form, whereas it must be changed to a declarative sentence. 'Would you' must be changed to 'if I would'. Hence B is incorrect.
Option C: This option is incorrect because 'tea' has been replaced with 'coffee'. This changes the meaning of the original question. Also, the tense of the verb 'leave' has not changed to past tense over here.
Option D: This option is an accurate version of reported speech for the given question. 'Would you' has been changed to 'If I would' and 'leave' to 'left'. Hence option D is correct.