Select the option that is related to the fifth term in the same way as the second term is related to the first term and the fourth term is related to the third term.

U144 : S121 :: N100 : L81 :: G64 : ?

E49

Pattern fllowed is :

U144 : S121

U(21) - 2 = (19)S & Adjacent terms follow patter :-   n²   :   (n-1)²

12²   :   (12-1)²

144 : 121

N100 : L81

N(14) - 2 = (12)L & Adjacent terms follow patter :-   n²   :   (n-1)²

10²   :   (10-1)²

100 : 81

Similarly ,

G64 : ?

G(7) - 2 = (5)E 

n²= 64 , n = 8

 (n-1)²  = (8-1)²

= 49

Hence , E49 is correct answer .