Choose the correct alternative from the given ones that will complete the series.

A, P, C, Q, E, R, G, ?, ?

A group of alphabets is given with each being assigned a number. These have to be unscrambled into a meaningful word and correct order of letters be indicated from the given responses.

$$\begin{gathered} E O C N A \\ 1 2 3 4 5 \end{gathered}$$

Find out wrong number in the given series.

$20, 40, 200, 400, 2000, 4000, 8000$.

Select the one which is different from the other three responses.

Select the related number from the given alternatives.

$64 : 144 : : 256 : ?$