Determine whether each of these conditional statements is true or false.

a) If 1 + 1 = 3, then unicorns exist.
b) If 1 + 1 = 3, then dogs can fly.
c) If 1 + 1 = 2, then dogs can fly.
d) If 2 + 2 = 4, then 1 + 2 = 3.