The correct answer is option 1: Frictional force.

Frictional force is a non-central force because it does not act through a single point; it is distributed across the contact area between two surfaces. In contrast, central forces act through a single point, such as the gravitational force or electric force acting between two point masses or charges.

Frictional force is also a non-conservative force. A force is considered conservative if the work done by the force on an object moving through a closed path is zero. However, the work done by frictional force is generally non-zero when an object moves along a closed path. This is because the frictional force opposes the motion of objects, causing energy loss in the form of heat due to interactions at the contact surface.

Option 2, the electric force, is a central force because it acts along the line joining the charges and is conservative in nature. Option 3, the gravitational force, is also a central force and is conservative. Option 4, mechanical force, is a general term and can include both central and non-central forces, so it is not a specific example of a non-central and non-conservative force.

In summary, frictional force is non-central and non-conservative, making it the correct