Tripping from Behind

[Freddy]

Situation: Defender's foot makes slight contact with the foot of the dribbler he is pursuing. Dribbler trips. Foul for illegal contact.
Question: With no official mechanic for "tripping", which signal should properly be used when reporting foul to the table, illustration #32 Blocking, or #33 Pushing?
Reason for asking:
10-6-6: Contact caused by a defensive player who approaches from behind
is pushing.
Yet,
4-7-1: Blocking is illegal personal contact which impedes the progress of
an opponent with or without the ball.