Answer
The given relation is not a function because each element of the first coordinate (number of children) will be paired with multiple elements of the second coordinate (members of the 50-women water aerobics class).
Work Step by Step
The first set, number of children, will be paired with multiple women from the water aerobics class.
$\\$This is because there are a lot of women members of the class that have 0 or 1 or 2 or 3 or 4 children.
$\\\\$Thus, the given relation is not a function.
