Find which one word cannot be made from the letters of the given word.
$OBSTETRICIAN$

Arrange the given words in alphabetical order and choose the one that comes first.

How many $D$'s are there in the following series which are immediately followed by $W$ but not immediately preceded by $K$?
$K, D, C, W, K, D, W, N, K, G, D, W, W, D, H, K, V, D, W, Z, D, W$

Arrange the given words in alphabetical order and choose the one that comes first.

How many meaningful words can be made from the letters $AEHT$,using each letter only once?

Each of the following questions is based on the following alphabet series.
$A, B, C, D, E, F, G, H, I, J, K, L, M$
$N, O, P, Q, R, S, T, U, V, W, X, Y, Z$
If the second half of the given alphabet is written in reverse order,which letter will be seventh to the right of the twelfth letter from the left end?