At point A, David observed the top of a tall building at an angle of 30°. After walking for 100m
towards the foot of the building, he
stopped
at point B where he observed it again at an angle
of 60°.Find the height of the building .​

The objects do not reach terminal velocity         there is not enough time from the time the object falls from when it hits the ground to achieve terminal velocity. an object must be placed higher to achieve terminal velocity in order to be in free fall.

Answertechnician (a) is correct;

I'm having some difficulty seeing the diagram clearly.but the question says there's a net inward force on the object.so we know right away,  from newton's 2nd law of motion, thatthat baby is accelerating.  it doesn't even matter which way thenet force is pointing.  if there's any net force, then either theobject's speed or else its direction must be changing.