Fill in the blank space for the given series with the correct alternative.
$12, 32, 72, 152, (\ldots)$

The following question is based on the five three-digit numbers given below:
$519, 368, 437, 246, 175$
Which of the following is the sum of the middle digits of the highest and the lowest numbers?

Fill in the blank space for the given series with the correct alternative.
$1, 4, 9, 16, 25, (\ldots)$

Fill in the blank space for the given series with the correct alternative.
$2, 9, 28, 65, 126, (\ldots)$

Find out the missing letters for the given series from the given alternatives.
$....aba.....cabc....dcba......bab.....a$

What should come next in the following number sequence?
$2, 2, 3, 2, 3, 4, 2, 3, 4, 5, 2, 3, 4, 5, 6, 2, 3, 4, 5, 6, 7, 2, 3, 4$