A toy helicopter is flying straight ahead. A fan is blowing air toward the helicopter's right.

When the helicopter flies past the fan, the fan will push the helicopter toward the helicopter's right. Which of the following must happen when the helicopter flies past the fan?
A.
the direction of the helicopter's motion will change
B.
the helicopter will speed up
C.
the helicopter will stop moving
D.
the helicopter will slow down

D. the helicopter will slow down