a)
We have the next forces
Fd that is the air drag force that is acting upward
Fd gravitation force that is acting downward
in other words
his weight is the force that acts downward and the force of the air resistance with the parachute act upward
b)
In this case, because he is falling at a constant velocity it means
So the net force on the skydiver is 0
therefore both forces are equal amount in other words the forces are equal in magnitude