A frog applies a constant force of 80N while pushing him up a hill, while gravity and legs
friction cause a constant 80N force in the opposite direction. In this situation
a. the frog applied force of 80N means the frog must be accelerating
b. the net force on the frog is 0N, which means the frog is not accelerating
c. the combined force of gravity and legs friction means the frog must be
decelerating
d. the frog can’t be moving up the hill, because the forces on it are balanced.
Write the detail of your above choice as well
This question is too unclear. The direction of the 80N force that the frog exerts "on the hill" must be specified. An equal and opposite force is exerted upon the frog, whether it is accelerating or not. The so-called "leg friction" is the force actually pushing the frog upwards. It is not a drag force.
Gravity acts down and leg friction acts up along the slope. They have to be added as vectors.
I have no idea what the writer of this question has in mind.