The graph shows the relationship between the total amount of money that Carly will have left, y, if she buys x packs of baseball cards.

A graph titled Money Left after Purchase. The x-axis shows packs of cards bought, numbered 1 to 9, and the y-axis shows the money left (in dollars), numbered 2 to 18. Blue diamonds appear at points (1, 16), (2, 12), (3, 8), (4, 4), (5, 0).
How much money will she have if she doesn't buy any packs of baseball cards?

$16
$18
$19
$20