If f is a function where f = {(1,2), (2,4), (3,6), (4,8)} and g is a function
where g = {(1,3), (3,5), (5 , 7)} , then f + g = .....
(a) {(1, 2), (2,4), (3,6),(4 , 8), (1,3), (3,5),(5,7)}
(b) {(1,2), (2 , 4), (3 , 6), (4,8) , (5 , 7)}
(c) {(1,5), (3 , 11)}
(d) {(1,5), (2, 4), (3 , 11),(4,8),(5,7)}