Forum:A priority question

If my opponent summons Black Rose Dragon, can i ask him if he wants to activate his priority n then chain in accordance? like e.g player a : "synchro summon black rose dragon", player b : "use its effect and bomb the field?" player a : "no" player b : "chain Bottomless Trap Hole " what happens now? can he still bomb the field w/ his priority? or did he miss his timing or something?