* A Fire: This could refer to the act of setting something ablaze (verb) or a burning blaze itself (noun).
* B Fly: This could refer to the act of moving through the air (verb) or an insect (noun).
* C Tire: This could refer to a rubber wheel on a vehicle (noun) or to become weary (verb).
A homograph is a word that is spelled the same as another word but has a different meaning. All three of these pairs fit that definition.