The graph below shows the fees for in-home pet care. Which statement best describes the slope of the graph?

The in-home pet care fee is $2.25 per hour.

The in-home pet care fee is $2.25 per hour.

The in-home pet care fee is $2.50 per hour.

The in-home pet care fee is $2.50 per hour.

The in-home pet care fee is $4.00 per hour.

The in-home pet care fee is $4.00 per hour.

The in-home pet care fee is $6.00 per hour.