Let R ={ (a,b),(c,d),(b,b)}, S = {(d,b),(c,b),(a,d)} then R composite S = ___________

• A. {(a,e),(c,b),(b,e)}
• B. {(d,b),(c,b),(a,d)}
• C. {(a,b),(b,b)}
• D. {(c,b)}