What should come in place of the question mark (?) in the given series based on the English alphabetical order?
BTD, YQA, VNX ,  ?,  PHR

Given: BTD, YQA, VNX , ?, PHR

Logic: Each letter decreased by -3 places in English alphabet.

First Letters: B → Y → V → ? → P
B - 3 = Y
Y - 3 = V
V - 3 = S

S - 3 = P
Second Letters: T → Q → N → ? → H
T - 3 = Q
Q - 3 = N
N - 3 = K

K - 3 = H
Third Letters: D → A → X → ? → R
D - 3 = A
A - 3 = X
X - 3 = U

U - 3 = R
So, the missing term is SKU.
Thus, the correct option is (b) SKU.​​