Find the integer a such that

a) a ≡ 43 (mod 23) and −22 ≤ a ≤ 0.

b) a ≡ 17 (mod 29) and −14 ≤ a ≤ 14.

c) a ≡ −11 (mod 21) and 90 ≤ a ≤ 110.

Find the integer a such that

a) a ≡ 43 (mod 23) and −22 ≤ a ≤ 0.

b) a ≡ 17 (mod 29) and −14 ≤ a ≤ 14.

c) a ≡ −11 (mod 21) and 90 ≤ a ≤ 110.