If the sequence of alphabets is reversed, which of the following will be the 14th letter?

There are $26$ letters in the English alphabet. To find the position of a letter from the beginning when the alphabet order is reversed, we can use the position conversion rule:
$$\text{Position from beginning}=27-\text{Position from end}$$

Given that we want the 14th letter from the end (in the reversed order):

$$\text{Position from beginning}=27-14=13$$

The 13th letter in the normal forward alphabetical sequence ($\text{A}=1,\text{B}=2,\dots$) is M.