The positions of the $5^{\text{th}}$ and $12^{\text{th}}$ letters of the word 'GLORIFICATIONS' are interchanged; and likewise the positions of the $4^{\text{th}}$ and $14^{\text{th}}$, $3^{\text{rd}}$ and $10^{\text{th}}$, $2^{\text{nd}}$ and $11^{\text{th}}$, and $1^{\text{st}}$ and $13^{\text{th}}$ letters are interchanged. Which of the following will be the $12^{\text{th}}$ letter from the right end?

Let's write the original word with indexed positions:
$$\begin{array}{cccccccccccccc}1& 2& 3& 4& 5& 6& 7& 8& 9& 10& 11& 12& 13& 14\\ \text{G}& \text{L}& \text{O}& \text{R}& \text{I}& \text{F}& \text{I}& \text{C}& \text{A}& \text{T}& \text{I}& \text{O}& \text{N}& \text{S}\end{array}$$

The question asks for the **$12^{\text{th}}$ letter from the right end, which corresponds to the $3^{\text{rd}}$ letter from the left end** in a $14$ -letter word (since $14-12+1=3$).

Let's find what happens to the element at position 3:
According to the instructions, the positions of the $3^{\text{rd}}$ and $10^{\text{th}}$ letters are interchanged.
Therefore, the letter originally at position 10 moves to position 3.
The letter at position 10 is T.
Thus, the $3^{\text{rd}}$ letter from the left end (which is the $12^{\text{th}}$ from the right end) becomes T.