Which of the following series observes the rule,"Skip in between adjacent letters,increasing one letter more each time to build a set of letters"?

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

Which one word can be formed from the following letters?
$a, a, d, e, f, g, r, s, u$

If the positions of the first and sixth letters of the word $BENEFICIAL$ are interchanged; similarly the positions of the second and seventh letters are interchanged and so on,which letter will be third from the right end after rearrangement?

Find which one word cannot be made from the letters of the given word.
$T R I B U N A L$

If it is possible to make a meaningful word with the second,the sixth,the ninth and the twelfth letters of the word $CONTRIBUTION$,which of the following will be the last letter of that word? If more than one such words can be made,give $M$ as the answer and if no such word is there,give $X$ as the answer.