To my mind the correct answer is (A).
"Many Americans travel to Costa Rica during the winter months, the peak season, because of the warmer temperatures found at many of Costa Rica’s tropical beaches and lush rain forests. "
In this sentence, the author decides to add additional information through an APPOSITIVE PHRASE. If the writer decides to delete "the peak season" from the sentence, the meaning of the sentence will remain.
Answer:
The son had showed his father a match. Whenever he lit the match, it filled the entire room with light, yet it was still small enough to fit into his pocket.
