Find out the wrong term from the given series.
$1, 5, 5, 9, 7, 11, 11, 15, 12, 17$

Study the following arrangement carefully and answer the question.
$O, 4, E, J, 5, T, 1, A, M, Q, 3, 8, N, I, K, 7, W, F, 6, S, 9, U, 2, Y, X$
If all the numbers in the above arrangement are dropped,which of the following will be the ninth to the left of $S$?

Choose the correct alternative to complete the series: $aab....aa....bbb....aaa....bbba$

Find out the wrong term from the given series.
$445, 221, 109, 46, 25, 11, 4$

To answer these questions, study the following arrangement of digits, letters and symbols carefully.

$6, N, P, =, @, 7, 1, \&, R, T, 3, L, B, \star, E, 4, \#, 8, G, H, \$, 5, K, M, ?, 2, D, C$

'$= N$' is to '$T 1$' and '$B 3$' is to '$G 4$' in the same way as '$EB$' is to

What will come in place of the question mark $(?)$ in the alphabetical sequence given below?
$A, C, A, B, B, D, B, C, C, E, C, ?$