For this question let:
A = {a, b, c, d} and R is a subset of A * A where,
R = {(a, a), (b,b), (c, c), (a, b), (b, c), (c, d), (d, c)}
a) The reflexive closure of R has how many elements?
b) The symmetric closure of R has how many elements?
c) The transitive closure of R has how many elements?