Determine if each of the following functions from $\lbrace a,b,c,d \rbrace$ to itself is one-to-one and/or onto.
Check ALL correct answers.
(a) $f(a)=b, f(b)=b, f(c)=d, f(d)=c$

A. neither one-to-one nor onto.
B. one-to-one.
C. onto.

$f(a)=b, f(b)=a, f(c)=b, f(d)=c$

A. onto.
B. one-to-one.
C. neither one-to-one nor onto.

$f(a)=d, f(b)=b, f(c)=c, f(d)=d$

A. one-to-one.
B. neither one-to-one nor onto.
C. onto.