Step 1: The question tests basic legal terminology used in medicolegal work, specifically the roles of people in a civil suit.
Step 2: A civil case begins when an aggrieved party approaches the court seeking a remedy. That initiating party is termed the plaintiff, the one who lodges or files the suit.
Step 3: Contrast this with the other roles. The party answering the complaint is the defendant, and the official who decides the matter is the judge. Neither of these matches the term plaintiff.
Step 4: Because a precise definition applies, the None option can be ruled out, leaving filing a case in civil court as the answer.
\[\boxed{\text{Files case in civil court}}\]