Correct option is A
The correct indirect speech is (a)
My niece told me that she had decided to take coaching in badminton.
Definition:
·
Direct speech: Quoting the exact words spoken.
·
Indirect speech: Reporting the words spoken, usually with a change in tense.
Rule of conversion:
· Change of pronoun: "I" → "she"
· Change of tense: Present Perfect ("have decided") → Past Perfect ("had decided")
· "Said" + to whom → "told me"
Example: He said, “I have completed the task.” → He said that he had completed the task.