[jjb]

on a running play A1 is being horse collared at B's 40 yard line and the ball comes loose. The ball is recovered by:
A2 on B's 35
A2 on B's 45
B1 on B's 35
B1 on B's 45

Where is the enforcement spot ?

( I'm new here and my chapter didn't hand the rules/case booklets out yet )

Thanks in advance