Read the given passage and answer the following question :

In 1953 that James Watson and Francis Crick, based on the X-ray diffraction data produced by Maurice Wilkins and Rosalind Franklin, proposed a very simple but famous Double Helix model for the structure of DNA. One of the hallmarks of their proposition was base pairing between the two strands of polynucleotide chains. However, this proposition was also based on the observation of Erwin Chargaff that for a double stranded DNA, the ratios between Adenine and Thymine and Guanine and Cytosine are constant and equals one. The base pairing confers a very unique property to the polynucleotide chains. They are said to be complementary to each other, and therefore if the sequence of bases in one strand is known then the sequence in other strand can be predicted.

The two polynucleotide chains of DNA molecule are :

(i) Identical

(ii) Complementary to each other w.r.t. base pairs 

(iii) A specific purine pairs with a specific pyrimidine 

(iv) The bases in two strands are paired through hydrogen bond (H-bonds) forming base pairs (bp).

(ii), (iii) and (iv) only 

The correct answer is Option (3) - (ii), (iii) and (iv) only

The two polynucleotide chains of DNA are complementary, meaning they are not identical but have sequences that complement each other through the specific pairing of bases (A-T and G-C). The two chains have anti-parallel polarity. It means, if one chain has the polarity 5'→3' , the other has 3'→5'.

The bases in two strands are paired through hydrogen bond (H-bonds) forming base pairs (bp). Adenine forms two hydrogen bonds with Thymine from opposite strand and vice-versa. Similarly, Guanine is bonded with Cytosine with three H-bonds. As a result, always a purine comes opposite to a pyrimidine. This generates approximately uniform distance between the two strands of the helix.