Fill in the blank space for the given series with the correct alternative.
$2, 5, 9, (\ldots), 20, 27$

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

Study the following arrangement carefully and answer the question given below:
$R, 4, E, J, 5, T, 1, A, M, Q, 3, 8, N, I, K, 7, W, F, 6, D, 9, U, 2, Y, V$
Which of the following is exactly in the middle between $A$ and $D$ in the above arrangement?

Second and third digits of each number given below are interchanged. Then,the $1st$ and the last digits of each new number thus formed are interchanged. Which of the following numbers then will be the highest number among the five?
$273, 372, 438, 184, 526$

Study the following arrangement carefully and answer the questions given below:
$R, 4, E, J, 5, T, 1, A, M, Q, 3, 8, N, I, K, 7, W, F, 6, D, 9, U, 2, Y, V$
If all the numbers in the above arrangement are dropped,which of the following will be the ninth to the left of $D$?

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 exactly in the middle between $A$ and $S$ in the above arrangement?