D H F J H K P R
4 8 6 10 8 11 16 18
Hence HK is odd one out.

704 ÷ 11 = 64 256 ÷ 4 = 64
832 ÷ 13 = 64 310 ÷ 5 = 62

2¹ = 2, 16 = 2⁴,
128 = 2⁷ & 56 = 7x 2³

All are squares except one number in the given option.

853 ? 8 = (5 + 3),
734 ? 7 = (3 + 4)
532 ? 5 = (3 + 2),
751 ? 7 = (5 + 1)

So odd number is 751 not following the pattern.

In all other pairs, the second number is 9 more than the first.

In all other pairs, first is the name of a desert which is situated in country denoted by the second

In all others, second is the part of first.

Belief is a different word from others.

'Nocturnal' is a different word because other words are related to music.