Which scatterplot demonstrates the strongest relationship between two quantitative variables?

A graph has x on the x-axis, and y on the y-axis. Points are scattered throughout the graph.
A graph has x on the x-axis, and y on the y-axis. Points curve up and then down in a line.
A graph has x on the x-axis, and y on the y-axis. Points increase loosely together.
A graph has x on the x-axis, and y on the y-axis. Points decrease loosely together.