Which of the following statements are not true?
(A) Two acute angles are always supplementary.
(B) Two obtuse angles are always supplementary.
(C) Two equal angles which are twice of the half of a right angle are supplementary.
(D) An acute and an obtuse angles are always complementary.
Choose the correct answer from the options given below.

Two acute angles add up to less than $$180^\circ$$ and two obtuse angles add up to more than $$180^\circ$$, so (A) and (B) are false. An acute and an obtuse angle together exceed $$90^\circ$$, so they can never be complementary and (D) is false. In (C), each angle is $$2 \times 45^\circ = 90^\circ$$ and $$90^\circ + 90^\circ = 180^\circ$$, so (C) is true; the false statements are (A), (B) and (D).