D detailed descriptions of each player’s reaction to the new coach This is the correct answer.
Spencer is a boy and tells about his experience with a new football coach. He got really surprised- stunned- when he met the new coach; it was a woman. He expected any coach but a female coach.He got speechless and he got so surprised that he could not hear what she said. Spencer's reaction could be more effective if he added the reaction of the other players. Certainly, all of them would be as stunned as Spencer . This chain of reactions would make the personal narrative more enganging.
These options are not right:
A a paragraph that clearly establishes the narrative’s point of view. ( An explict reflection would make the narrative less effective. The reader has to feel the writer's attitude).
B engaging dialogue that tells the reader what the coach says to the team ( The focus is on the writer's reaction. In fact, what the coach actually said was not important).
C a thoughtful reflection that explains what the coach teaches Spencer. ( This is not important. The coach is a football coach and the stunning fact is that it is a woman).