Block/Charge/Player Control?

[RookieDude]

QUESTION:

A1 is running toward A's goal but is looking back to receive a pass. B1 takes a position in the path of A1 while A1 is 10 feet away from B1...A1 receives the ball and before taking a step contacts B1.
Since the position of B1 is legal when A1 has the ball, the contact is ________?

a. Block by B1

b. Player Control by A1

c. Charging by A1

Which of the above answers "best" describes the situation per NFHS rules? a, b, or c?

Dude