Suppose four people are sitting at a table. Let U be the set of people sitting at a table, U = {A, B, C, D]. The people are seated as in the figure.

A D B C

Draw the graphs of the following relations that are subsets of U X U and specify which of the relations are functions.

(a) { (x, y) | x sits next to y)

(b) {{x,y)\x sits across from y}

(c) { (x, y) | x sits to the right of y\.