Use the matrix representation of relations to compute the following

Let . Let be a relation on the set . Use the matrix representation of relations in order to compute the following:

a) Let be the reflexive closure of . Compute .

My current answer is

b) Let be the transitive closure of . Compute . (I used Warshall's algorithm)

My current answer is

c) Let . Compute the symmetric closure of and call this set .

My current answer is

d) Prove or disprove that is an equivalence relation on the set . If is an equivalence relation, then list the elements in each of the equivalence classes. If is not an equivalence relation, then list what elements need to be added to to make it an equivalence relation.

(I have not completed this part yet, so I could use a hand here)

I mainly need to know whether my work on the first three parts has yielded correct answers (it'd be pretty easy to make a mistake). As for the last part, any help would be appreciated.