Fill in the blanks with acute, obtuse, right or straight:

(a) An angle whose measure is less than that of a right angle is _______.

(b) An angle whose measure is greater than that of a right angle is _______.

(c) An angle whose measure is the sum of the measures of two right angles is _______.

(d) When the sum of the measures of two angles is that of a right angle, then each one of them is _______.

(e) When the sum of the measures of two angles is that of a straight angle, and if one of them is acute then the other should be _______.