con man
If we assume that there is only one liar among A, B, and C, then the liar is C. This is because if A or B were the liar, the statements of A and B would contradict each other. However, C's statement allows for the possibility that they are lying, making C the most likely candidate to be the liar.
conversation or communication
Carmen ("C" is spelled as "K" and the whole is girl's name)
Corsica is a French island that starts with a "C."
Some c words meaning person would be character, child, and customer. Another could be Klingon.
Car is another word for truck that starts with a "c".
consomme
Credenza
cabana
casa
civilianscommonerschaps
Catastrophic
converse.
Cove
Chilly, coldish
celebration
consequence