Final answer:
Mrs. Clara Post fell five flights after she was distracted by a kitten's mewing, leading to her death.
Step-by-step explanation:
According to the dialogue provided, Mrs. Clara Post apparently fell five flights due to being distracted by a kitten's mewing. This unfortunate incident led to her death, as indicated by the mention of her falling to the courtyard below. No mention of her winning a medal, adopting a kitten, or going on a picnic is given in the excerpts provided. Therefore, option b) She fell five flights is the correct answer to what happened to Mrs. Clara Post as mentioned in the dialogue.