A's ball 1st & 10 at A35. A1 hands off to A2 who tries running around end 1)A5 holds at A33 yard line or 2)A5 holds at A37 yard line and is tackled at A45 yard line. Where is the spot? Thanks in advance

FED:

All-But-One Principle. Basic spot for a running play is the end of the run with the exception of foul by the offense occurring behind the basic spot during a loose ball play or running play. This particular foul is enforced from the spot of the foul.

In both 1 and 2 foul occurs behind the basic spot and are therefore enforced from the spot of the foul. 1) the 33 and 2) the 37.