Question

if an american salutes the flag to show his love of the country ,he is treating the flag as a 1)symbol. 2)metaphor. 3)inference

Answer 1

The correct option is SYMBOL.
A symbol refers to an object or character which is used as a conventional representation of an object, process or function. Symbol is a thing which stands for another thing. 
In the question given, the flag stands for United States of America.

Answer 2

A Symbol because the other one's don't make since.