19) The graph below describes the labor cost for a mechanic. Which of the following describes the domain of the function? A Mechanic's Labor Cost A All real numbers 320 B All real numbers greater than or equal to 0 280 © All whole numbers greater than 1 240 Labor cost, C(h) 200 D All whole numbers greater than 75 120 80 40 W 1 4 5 6 7 Hours, h