Which sentence is a comma splice?

Question

A. While the lawyer prepared the case,
her assistant checked the report she
found no mistakes.

B. Because all the members were early,
the meeting got underway ahead of
schedule.

C. Dr. Matheson,speaking as head of the
hospital's medical council.

D. The secretary handed the report to
the supervisor,he read it quickly.

I think it's sentence D.

AM I CORRECT?

Very good!

is b.