An object becomes positively charged when it
a. loses electrons.
b. loses protons.
c. gains electrons.
d. gains neutrons.

The correct answer is Option a.

Explanation:

There are 3 sub-atomic particles in an atom.

1.) Protons: These particles are positively charged particles and are present inside the nucleus.

2.) Electrons: These particles are negatively charged particles and are present around the nucleus. These can be easily lost or gained. When the electrons are lost, the atom will gain a positive charge and when electrons are gained, the atom will carry a negative charge.

3.) Neutrons: These particles does not carry any charge on them and their loss or addition will not cause any effect on the atom.

Hence, the correct answer is option a.