Determine if the function defined below is one-to-one, onto, both, or neither.
f:X→Y
where
X= {a,b,c,d), Y={1,2,3,4}
and
f(a)=4, f(b)=2, f(c)=1, f(d) = 3.
a. One-to-one
b. Onto
c. Both one-to-one and onto
d. Neither one-to-one nor onto