3. (1+1+1=3 points) Let D = \{0,1\} and E = \{x,y\}.
(a) Find the set D \times E.
(b) Give an example of an onto function from D \times E to C = \{a, b, c, d\}.
(c) Give an example of a function from D \times E to C = \{a, b, c, d\} which is not onto.