Claimant or plaintiff

I’m undergoing some practice objective questions and the following asks:

Which of the following is the name used for the person who commences a civil action?
A: Appellant
B: Plaintiff
C: Claimant

I answered Plaintiff but got the answer wrong, the correct one being C according to the answers.

However aren’t both B and C correct?

This was a question posed in the Kaplan Exam Kit 2020/21