If each participant of a chess tournament plays exactly one game with each of the remaining participants, then 171 games will be played during the tournament. Find the number of participants. Choose the correct choice from the following answers.
A) 15	B) 16	C) 17	D) 18	E) 19

Rationale: "let p be the number of participants . pc 2 = 171 ( p ) ( p - 1 ) = 342 = 19 * 18 p = 19 the answer is e ."
Answer: E