If X={1,2,3,4,5} and Y={1,3,5,7,9} determine which of the following sets are (i) mappings (ii) relations (ii) neither of X to Y.
(a) R1=(x,y):y=x+2,x∈X,y∈Y
(b) R2 ={(1,1),(2,1),(3,3),(4,3),(5,5)}
(c) R3 ={(1,1),(1,3),(3,5),(3,7),(5,7)}
(d) R4 ={(1,3),(2,5),(4,7),(5,9),(3,1)}