Choose the correct alternative answer

$a...bbbc...aab....cca....bbcc$

Choose the correct alternative to complete the series: $a . c a . b e . b c c . . . b c a$

Fill in the blank space for the given series with the correct alternative.
$1, 9, 17, 33, 49, 73, (...)$

Find the missing term for the given series from the given alternatives:
$BXJ, ETL, HPN, KLP, ?$

Study the following arrangement carefully and answer the question.
$O, 4, E, J, 5, T, 1, A, M, Q, 3, 8, N, I, K, 7, W, F, 6, S, 9, U, 2, Y, X$
Four of the following five are alike in a certain way based on their positions in the above arrangement and so form a group. Which is the one that does not belong to this group?

Find the missing letters for the given series from the given alternatives:
$aaa....bb....aab.....baaa....bb$