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: Unexpected triplets. Sentence 1: Emma was having a hard time conceiving. Sentence 2: So she and her husband went to see a fertility specialist. Sentence 3: He gave her hormones to help her get pregnant. Sentence 4: She lucked out and got pregnant the first month of trying. Choices: a. Her first ultrasound revealed she was having triplets! b. Now her backside is leaner, firmer and in a much better shape.

a