Four pairs of numbers have been given, out of which three are alike in some manner, while one is different. Choose out the odd one.

Given Option  (B),(C), (D)

are same and follow that pattern 

(B) 21: 462  that is follow the pattern $$21 \times 21 = 441  +21 = 462 $$

(C) 14: 210 it is follow the same pattern $$ 14\times14 = 196 + 14 = 210 $$

(D) 25:650 it is follow the also the above pattern $$ 25\times 25 = 625 +25 = 650 $$

but  Option (A) 7:50 it is not follow that pattern $$ 7^2 = 49 +1 = 50 $$

therefore Option (A) 7:50 is different pattern follow of the given option  hence it is Odd .

so (A)7:50 Ans