option character in a sentence

1. The format of parameters given to a program was not standardized, so that there was no single option character that differentiated options from file names.
2. The main character of the Chariot and Midnight Wanderers games Lou, was used as an assist only character for Marvel vs . Capcom he also had the option character from Midnight Wanderers known as Firestorm with him.
3. It's difficult to find option character in a sentence.