See the answer below.
Work Step by Step
a) A and D: central atom is $sp^2$ hybridized, so the angle is approximately 120°. B and C: central atom is $sp^3$ hybridized, so the angle is approximately 109°. b) Carbons 1 and 2 are $sp^2$ hybridized because they make a double bond, carbon 3 is $sp^3$ hybridized because it makes 4 single bonds.