This is just a guess, sorry if it's wrong but I think it's B
I think the correct answer is
(A) changing in abiotic factors
The answer is the third one!! :)
<span>The answer is DNA. There are several ways to obtain DNA samples, like blood, saliva, semen or hair. They are very important to guarantee a certified verification of the people involved with the situation and guarantee the best investigation possible of the event.</span>