Choose the correct alternative to complete the series: $ac...cab...baca...aba...acac$

Choose the correct alternative for the missing terms in the series: $R, M, ?, F, D, ?$

Fill in the blank space for the given series with the correct alternative.
$(2,3), (3,5), (5,7), (7,11), (11,13), (\ldots)$

Choose the correct alternative for the missing term.
$?, siy, oeu, kaq, gwm, cri$

Fill in the blank space for the given series with the correct alternative.
$1, 8, 27, 64, 125, 216, (\ldots)$

Study the following arrangement carefully and answer the questions given below:
$R, 4, E, J, 5, T, 1, A, M, Q, 3, 8, N, I, K, 7, W, F, 6, D, 9, U, 2, Y, V$
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?