Alphabet Test — “In the English alphabet, which letter is 10th from the right?” (Use R + L = 27; count from Z on the right.)

Introduction / Context:
This problem asks for a position counted from the right end of the 26-letter English alphabet (right means Z→A). Converting cleanly between “from left” and “from right” prevents off-by-one mistakes.

Given Data / Assumptions:

• Alphabet length = 26.
• R denotes the right index (from Z); L denotes the left index (from A).
• We seek the letter at R = 10.

Concept / Approach:
The conversion identity is R + L = 27. Thus for a given right index R, the left index is L = 27 − R. Identify the letter by its left index L.

Step-by-Step Solution:

Verification / Alternative check:
Direct right count: Z(1), Y(2), X(3), W(4), V(5), U(6), T(7), S(8), R(9), Q(10). Matches Q.

Why Other Options Are Wrong:

Common Pitfalls:
Forgetting that A is 26th from the right and Z is 1st from the right; always use R + L = 27.

Final Answer:
Q