If `x=a,y=b` is the solution of the pair of equations `x-y=2` and `x+y=4,` then the value of `a` and `b` are :
(a) `a=3,b=3`
(b) `a=3,b=2`
(c) `a=3,b=1`
(d) `a=3,b=-3`