To solve this logical reasoning question, let's break it down step-by-step:

1. First, note the full English alphabet series: A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z
2. The task specifies that the second half of the alphabet series should be written in reverse order. The second half of the alphabet (letters after M) is: N, O, P, Q, R, S, T, U, V, W, X, Y, Z
3. Reversing the second half results in: Z, Y, X, W, V, U, T, S, R, Q, P, O, N
4. The combined series now looks like this: 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
5. Now, identify the twelfth letter from the left in this modified sequence. It is: L
6. Next, determine the letter that is seventh to the right of L. Starting from L:
   • 13th letter: M
   • 14th letter: Z
   • 15th letter: Y
   • 16th letter: X
   • 17th letter: W
   • 18th letter: V
   • 19th letter: U
7. Thus, the seventh letter to the right of L is U.

The correct answer is U.