Directions: Identify the term that completes the given alphanumeric series.

Y4, W9, U16, S25, Q36, ?

The correct option is O49.

To find the missing term in the given series Y4, W9, U16, S25, Q36, ?, we analyze the pattern for both the alphabetical and numerical components separately.

1. Pattern of the letters:
Let us observe the position of each letter in the standard English alphabetical order (where A = 1, B = 2, ..., Z = 26):
Y = 25
W = 23 (25 - 2)
U = 21 (23 - 2)
S = 19 (21 - 2)
Q = 17 (19 - 2)
The pattern shows that each consecutive letter is obtained by decreasing the alphabetical position by 2.
Therefore, the next letter is:
17 - 2 = 15, which corresponds to the letter O.

2. Pattern of the numbers:
Now, let us examine the numerical sequence:
4 = 2²
9 = 3²
16 = 4²
25 = 5²
36 = 6²
The numbers are consecutive perfect squares starting from 2².
Therefore, the next number in the sequence is:
7² = 49.

Combining the letter and number components gives the term O49.