Boundary Plane Foul

[Joel Poli]

NFHS Rules:

A1 has the ball OB for a sidline throw in. During the throw in, A1 has the ball on the inbounds side of the boundary plane. B1 in his attempt to dislodge the ball, fouls A1 on the arm.
I know by rule if B1 reached through the boundray plane and fouled A1, it would be an intentional personal foul. In the situation above, the foul happens on the inbound side of the boundary plane. Would you call a common foul or stay with the intentional personal?
If you have a rule # or casebook play please cite the rule .

Thanks,