BITSAT 2019 Slot 2 Solved Paper

Due to size and geometries of bases, the only possible pairing in DNA are between G (guanine) and C (cytosine) through three H-bonds and between A (adenine) and T (thymine) through two H-bonds.
Thus,the complementary strand of DNA will be

A	T	C	G	T	A	T	G
↓	↓	↓	↓	↓	↓	↓	↓
T	A	G	C	A	T	A	C

(complementary strand)