Can you me with this question .

dna is made of two chains of nucleotides. which type of bonds hold the chains together?
a= hydrogen bonds
b= covalent bonds
c= ionic bonds
d= polar covalent bonds

Option A, Hydrogen bonds

Explanation:

Hydrogen bond between the bases holds the two strands of double helix together. There are four base namely Adenine (A), Cytosine(C), Guanine (G) and Thymine (T) which forms complementary base pairs.

There are two base pairs – A = T and C = G which are bonded by hydrogen bonds which can be easily broken for DNA replication.  

Hence, option A is correct.