Given the task definition and input, reply with output. 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: Poison Ivy. Sentence 1: I had been immune to poison ivy my entire life. Sentence 2: Two summers ago I went for a walk in the woods. Sentence 3: Hours later, itchy bumps formed on my hands. Sentence 4: I panicked because I didn't know what was wrong. Choices: a. A friend told me I was no longer immune to poison ivy. b. All of Inez's friends politely declined the invitation.
a