Choose the correct alternative answer

$m....nm....n.....an.....a....ma.....$

Study the following arrangement carefully and answer the question.
$O, 4, E, J, 5, T, 1, A, M, Q, 3, 8, N, I, K, 7, W, F, 6, S, 9, U, 2, Y, X$
Which of the following is the sixth to the left of the eleventh from the left end of the above arrangement?

Fill in the blank space for the given series with the correct alternative.
$13, 32, 24, 43, 35, (\ldots), 46, 65, 57, 76$

The positions of how many digits in the number $53147926$ will remain unchanged after the digits within the number are rearranged in descending order?

The positions of the first and the fifth digits in the number $53216894$ are interchanged. Similarly,the positions of the second and the sixth digits are interchanged,and so on. Which of the following will be the second from the right end after the rearrangement?

What should come next in the following letter series?
$nsi, org, pqe, qpc, ?$