Correct Answer: Anna was surprised and asked Mark what he was talking about. She further asked him how he could leave them alone at such a difficult time.

Solution : The first option is the correct choice.

Indirect speech, also known as reported speech or indirect discourse, is a way of reporting what someone else has said without quoting their exact words.
Narration conversion:

• The reporting verb "said" is changed to "asked".
• The present continuous tense "am talking" is changed to the past continuous tense "was talking".
• The modal "can" is changed to its past form, "could".
• The question words "what" and "how" are used as conjunctions in both sentences to emphasise the interrogative nature of the sentence.

Therefore, the indirect form would be: Anna was surprised and asked Mark what he was talking about. She further asked him how he could leave them alone at such a difficult time.