Team B leads Team A 24-22, with 12 seconds to go in the 4th quarter, 1st and 10 at Team B's 40 yard line. A5's pass is complete to A21, who is tackled in bounds by B2 at the B 31, one yard of the first down with 5 seconds on the clock. B2 after making the tackle holds A21 down to prevent the ball from being given to the referee/spotted, and time expires. What foul if any?