A charged comb picks up bits of paper because of:
A. Magnetic force
B. Gravitational force
C. Contact force
D. Electrostatic force

Hint: As we know that other than negative and positive charge, there also exists a neutral charge. A neutral charge is the charge that induces in the absence of the net charge. When a body is charged, whether positive or negative, it will always attract neutral objects.

Complete answer:
We know that every object consists of atoms that are small uncharged particles. Atoms consist of a positive center that contains small charged particles. These charged particles will be protons and neutrons, and negatively charged electrons that revolve around the positive center just like planets revolve around the sun.

When a comb is rubbed with a charged body, it will acquire a charge. This charge that is created by rubbing two objects is known as static electricity. The comb will acquire either negative charge or positive charge. Now, the paper will acquire a neutral charge because the net charge in the paper is absent.

Now, when the comb is brought near the pieces of paper, the paper piece will get attracted towards the comb. This is because the charge from the comb will get shifted towards the pieces of paper. This charge acquired by rubbing two objects is known as static electricity.Therefore the force acting on the charges is known as electrostatic force.

ence, option D is the correct option.

Note:As we know that when the comb is rubbed with cloth or hair, it acquires a charge and this charge is shifted towards the piece of paper when the comb is brought near the paper. The shifting of charge will arise in two cases, that is, within the paper and the part where the comb is brought. It is said that when the comb is rubbed with hair, it becomes negatively charged.