Fill in each blank with the correct form of the adjective in parentheses.
A) Of the five cows,the shorter one is the _______(big/biggest) of them all.
B) He is the ______(cleverest/cleverer) of the two.
C) Her ______(eldest/oldest) child is only five ,so she can't be very old.
D) The country is getting ______(dry/drier and drier) everyday.