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.
If I remember correctly the answer is, C) he realizes that he may be able to save Elizabeth from a death sentence.
The novel uses first-person narration to show Grendel’s perspective.
D) Verb: has been raining Mood: indicative
The entire verb phrase is "has been raining". "Has" and "been" are both helping verbs that create the present progressive tense. This tense is used to show something that is happening and has been happening for a period of time. The indicative mood is correct because the indicative mood indicates something that fact. Interrogative mood is question form. Conditional form is based on something else happening.