Final answer:
Meredith Grey's son on Grey's Anatomy is named Derek, after his father Derek Shepherd.
Step-by-step explanation:
The question refers to a character from the television series Grey's Anatomy. Meredith Grey, the main character, has a son whose first name is Derek. He was named after his father, Derek Shepherd, who was also a main character on the show. The correct answer to the question 'What is Bailey's first name (Meredith's son)?' is B) Derek. This is a piece of trivia related to the medical drama genre of television entertainment.