In the DNA double helix, how are the two strands of DNA held together?

Answer:
Option D
Explanation:
The DNA strands are composed of nucleotides which consists of sugar, phosphate and nitrogenous bases. The base pairs of one DNA starnd bind to the base pair of other DNA strand. The nitrogenous bases in the two strands of DNA make pairs such as A binds with T and C binds with G.
These base pairs are held together by the hydrogen bonds which are weak molecular forces.
Hence, option D is correct