Question

Name the missing force... Normal    Spring    Tension    Air Resistance

Answer 1

the missing force is spring force.

The object is hanging from the spring and the spring is stretched by some distance from its equilibrium position.  due to this stretch in the spring , a spring force starts acting on the object trying to regain its equilibrium position.

the spring force is given as

F = kx

where F = spring force ,k = spring constant , x = stretch in the spring.

the spring force balances the weight of the object in down direction and hence keeps the block from falling down.