Four letter-clusters have been given, out of which three are alike in some manner and one is different. Select the letter-cluster that is different.

WEKP

 1   2    3    4   5    6   7     8    9  10  11  12  13

 A   B   C    D   E    F   G    H    I    J    K    L   M

 ↓    ↓    ↓    ↓    ↓     ↓   ↓    ↓     ↓   ↓    ↓    ↓    ↓

 Z   Y    X   W   V    U   T    S    R   Q   P    O   N

26  25  24  23  22  21  20  19  18  17  16  15  14

THE LOGIC FOLLOWED HERE IS;

1) FUBY,

F(6) +U(21) + B(2) +Y(25)

= 54

2) WEKP,

W(23) +E(5) +K(11) +P(16)

= 55

3) SHOL,

S(19) +H(8) +O(15) +L(12)

= 54

4) PKRI,

P(16) +K(11) +R(18) +I(9)

= 54

Thus, WEKP is  the letter-cluster that is different.