Final answer:
To make a legal free pass in basketball, the pass needs to be made with two hands and must be lateral or backwards, with no requirement for an underhand throw or for the ball to touch the inside of the player's foot.
Step-by-step explanation:
When making a legal free pass in basketball, the pass must be done with two hands, and it must be either lateral or backwards; a forward pass is not permitted. No underhand throw is specifically required, and while the ball may touch the inside of a player's foot during a play, this is not a requirement for the legality of a free pass. Therefore, the answer to the question what must occur in order to make a legal free pass is C) The pass must be lateral or backwards.