You will be given a definition of a task first, then some input of the task.
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: Polarised Humanity. Sentence 1: Yuri was living in terrible conditions in Syria. Sentence 2: He feared for his life every day. Sentence 3: After a nearby bomb attack, he spent hours clearing the rubble. Sentence 4: After 2 days of clearing, they heard a child shouting. Choices: a. 3 hours later, they had recovered a 4 year old boy from the ruins. b. I was able to quit heroin.
Output:
a