Questions

Brihanmumbai Municipal Corporation (BMC), is the governing civic body of Mumbai, the Municipal Corporation of Greater Mumbai, Maharashtra is India's richest municipal corporation. The BMC's annual budget exceeds that of some of the smaller states of India.

(1+9+6+8+3) x (1+9+6+8+3) x (1+9+6+8+3) = 19683

Kerala

Combining drugs usually leads to more intense effects on our health.

The logic in the given puzzle is 

Addition of numeric values of corresponding letters in the first three figures gives respective corresponding letter in fourth figure. 

i.e, A = 1 , W = 23 , B = 2 => 2 + 1 + 23 =26 = 'Z'

Similarly, L = 12, K = 11 , A = 1 => 1 + 11 + 12 = 24 = 'X'

Here the missing letter is 'X'.