The non contact force is :
(a) force of reaction (b) force due to gravity
(c) tension in string (d) force of friction
Answer: (b) force due to gravity
The forces which act on bodies when they are in physical contact. are called contact forces. For e.g. frictional force and force exerted on two bodies during a collision.
The forces experienced by bodies even without being physically touched are called the non-contact forces. For e.g. Gravitational force and Electrostatic force.