In this task, you're given the title of a five-sentence story, the first four sentences, and two options for the fifth sentence as a and b. Your job is to pick the sentence option that seamlessly connects with the rest of the story, indicating your choice as 'a' or 'b'. If both sentences are plausible, pick the one that makes more sense.

Title: Whale. Sentence 1: Nita had always wanted to see a whale. Sentence 2: She had been on 3 whale-watching tours, with no luck! Sentence 3: But then she went on a diving trip with her friends. Sentence 4: There, she saw a huge whale in its natural habitat! Choices: a. But Kia and Ana remained pen pals for years! b. Nita was thrilled and overjoyed!
b