Choose the correct order of the given alternative : Z _ 25 Y B 23 X C _ W _ 19 _ E 17

Explanation:-

From the alternatives, it is clear that the series can be divided in to 5 groups of three terms each - each group comprising of two letters followed by a number.
Z _ _ 25/ YB23 / XC _ _ / W _ 19 / _ E 17
Observing the group Y B 23, we find that in a group, the number is the difference of the numbers representing the positions of the two letters in the English alphabet.
Thus, putting A = 1, B = 2, ......Y = 25, Z = 26, we have
Y - B = 25 - 2 = 23.
Similarly, missing term in 1st group = Z - 25 = 26 - 25 = 1 = A So, the first and second missing terms are A and 21 respectively, which are given only in (A).