Given the task definition, example input & output, solve the new input case.
In this task, you're given four sentences of a story written in natural language. The given story is not complete and your job is to complete the story by selecting one of the sentence choices from (A) and (B), such that the story sounds fully coherent.
Example: Sentence1: Rick grew up in a troubled household. Sentence2: He never found good support in family, and turned to gangs. Sentence3: It wasn't long before Rick got shot in a robbery. Sentence4: The incident caused him to turn a new leaf. 
 (A) He is happy now. (B) He joined a gang.
Output: A
As mentioned in fourth sentence, the incident turned a new leaf to Rick's life; so, he must be happy now.

New input case for you: Sentence1: Brian was asked to watch his friends dog. Sentence2: They left a notebook to keep a log. Sentence3: He would update it with the times he went there. Sentence4: Right before he came back he left a message regarding their time. 
 (A) He was happy that his friends considered him trustworthy. (B) He had to admit he didn't really like their cat very much.
Output:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
A