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: Environmental Volunteerism. Sentence 1: Leah feels very strongly about helping the environment. Sentence 2: She decides to research how she can best help. Sentence 3: She discovers a volunteer organization specializing in the environment. Sentence 4: Leah participates in several park cleanups. Choices: a. Tina is now preparing to tell her family the pregnancy news. b. Leah is proud of herself for being able to help the environment.
b