At Trial, the First Step in Laying the Foundation for the Introduction

At trial, the first step in laying the foundation for the introduction of a gun is to have someone:

A) identify the gun being introduced at trial and testify where it was found.
B) identify the gun being introduced at trial as the gun found in the possession of the defendant.
C) identify the gun being introduced at trial as the one the defendant used while committed the crime he/she is now charged with committing.
D) identify the gun and explain the results of tests they conducted on it.