What Is the Reason for Accounting for an Object's Whereabouts

What is the reason for accounting for an object's whereabouts from first discovery to trial?

A) In order to establish that the evidence was not planted.
B) In order to establish that the object was used by the defendant to commit the crime.
C) In order to establish that the object was not altered or tampered with.
D) So that the defendant cannot gain access to it.