Which statements below correctly describes the process of reduction in a redox reaction. Choose the 2 correct statements.

a
Occurs when the oxidation number of an element increases in chemical reaction.
b
Occurs when atoms gain electrons during bonding.
c
Occurs when atoms lose electrons during bonding.
d
Occurs when the oxidation number of an element decreases in chemical reaction.

The correct statements that describe the process of reduction in a redox reaction are:

b. Occurs when atoms gain electrons during bonding.
d. Occurs when the oxidation number of an element decreases in chemical reaction.