Answer
The force at point A from the calf muscle must be directed upward.
Work Step by Step
We can consider the net torque about a rotation axis at point B.
Since the foot is in equilibrium, $\tau_{net} = 0$
Note that the floor pushes up at point P with a force of $900~N$
There is a counterclockwise torque about the rotation axis from the force from the floor.
In order to balance this torque, there must be an opposing clockwise torque from the force of the calf muscle at point A.
In order to cause a clockwise torque, the force at point A from the calf muscle must be directed upward.
