Number of letters skipped in between adjacent letters in the series increases by one. Which of the following series observes this rule?

Each of the following questions is based on the following alphabet series.
$A, B, C, D, E, F, G, H, I, J, K, L, M$
$N, O, P, Q, R, S, T, U, V, W, X, Y, Z$
Which letter is seventh to the right of the eighteenth letter from the right end of the alphabet?

Arrange the given words in alphabetical order and choose the one that comes in the second place.

$A$ group of letters is given which are numbered $1, 2, 3, 4, 5$ and $6$. Below are given four alternatives containing combinations of these numbers. Select the combination of numbers so that the letters arranged accordingly form a meaningful word.
$R, T, A, N, U, E$
$1, 2, 3, 4, 5, 6$

In the following series,count each $N$ which is immediately followed by $X$ but $X$ is not immediately followed by $T.$ How many such $N's$ are there?
$N, X, N, T, Q, M, N, X, T, M, X, N, X, C, N, Q, M, N, N, X, Q, N, X, T, X, N, A, M, X, N, X, M$

Arrange the given words in alphabetical order and choose the one that comes in the middle.