Simplify the following expressions to reduce to three terms:

a) A'C'D+A'BD+ABC+ACD'

b) A'B'C'+ABD+A'C+A'CD'+AC'D+AB'C'

c) BC'D'+ABC'+AC'D+AB'D+A'BD'

d) (A'+C'+D)(A'+B+C)(A+B+D)(A'+B+D)(B+C'+D)