During DNA renaturation, two DNA strands will:

a. break the hydrogen bonds that hold the two strands together with no effect on the covalent bonds that hold the nucleotides together.

b. break the covalent bonds that hold the nucleotides together while maintaining the hydrogen bonds that hold the two strands together.

c. Re-form a double helix if the two strands have complementary sequences.

d. Re-form a double helix if the two strands are identical in sequence.

Option C

Explanation:

DNA renaturation or annealing can be defined as the formation of base pairs and complementary DNA strands to reform. This occurs when the double stranded DNA is heated above its melting temperature and then under appropriate conditions, the temperature is slowly decreased.

This is in contrast to DNA denaturation where double stranded DNA is separated into single strands breaking the hydrogen bonds linking them together under appropriate conditions including elevated temperature etc.