Last second shot

[Redneck Ref]

First off some of you guys dog Rookie Dude because you think he's a rookie. Names can be deceiving. RD is a 14 year vet, number 2 in our association, our rules chairman, last 2 years state tourney, etc...a rookie by no means. Second RD is having a lot of fun with you guys.

Next, if full court pressure, and all 10 players are in the back court (lead is at half court)long pass and player A catches pass at top of key and turns and shoots...Who signals 3 point shot?