Suppose $U=\{1,2,3,4,5,a,b,c\}$ is a universal set with the subset $A=\{a,b,c,1,2,3,4\}.$ Which one of the following alternatives represents a surjective function from $U$ to $A?$

a$.\{(1,4),(2,b),(3,3),(4,3),(5,a),(a,c),(b,1),(c,b)\}$

b$.\{(a,1),(b,2),(c,a),(1,4),(2,b),(3,3),(4,c)\}$

c$.\{(1,a),(2,c),(3,b),(4,1),(a,c),(b,2),(c,3)\}$

d$.\{(1,a),(2,b),(3,4),(4,3),(5,c),(a,a),(b,1),(c,2)\}$