PLEASE HELP!! MEDAL AND FAN!!
The graph shows the production of cars per day at a factory during a certain period of time. What is the domain of this function during this period?

Graph of days versus cars. Points are plotted at the following coordinates: 0 comma 0, 1 comma 50, 2 comma 100, 3 comma 150, 4 comma 200, 5 comma 250, 6 comma 300, 7 comma 350, 8 comma 400, 9 comma 450.

The domain is all real numbers 0 through 9.

The domain is all integers 0 through 9.

The domain is all positive real numbers.

The domain is all positive integers.

Question

PLEASE HELP!! MEDAL AND FAN!!
The graph shows the production of cars per day at a factory during a certain period of time. What is the domain of this function during this period?

Graph of days versus cars. Points are plotted at the following coordinates: 0 comma 0, 1 comma 50, 2 comma 100, 3 comma 150, 4 comma 200, 5 comma 250, 6 comma 300, 7 comma 350, 8 comma 400, 9 comma 450.

 The domain is all real numbers 0 through 9.

 The domain is all integers 0 through 9.

 The domain is all positive real numbers.

 The domain is all positive integers.