hmm...this question has the look of a multiple guess question from an exam...so let's take a look from that angle.
These are your only four choices and you have to choose one....which would it be?
My answer would be "D", Two fingers on the trigger guard.
"A" and "B" may ruin fingerprints, and "C" is just plain stupid.
My answer would have to be E none of the above.
As said before, the police are there for a reason and it's their job to control and secure crime scenes.