forward latteral

[DJ_NV]

OK I'm having a total brain meltdown here (I'll blame it on the Canadian rules). Forget the fumble recovery by A for a moment. Now, if there is a change of possession during a down (B intercepts A) and only B fouls after the COP (normal live-ball foul), then are there any penalty options for A?

Let's assume 1/10 @ 50. B intercepts a forward pass at the B-30 and runs to the B-45 and is downed. During the return, B99 clips at the B-40. Are there any options besides backing B up 15 from the spot of the foul and going 1/10 for B?

Now to follow up on the original post, we're saying that A cannot take the ball because the penalty has to be enforced?

thanks