So the domain is the list of x-values that are possible on a line.
In this case since time is the x-axis, this means that he ran the race from 0 to 11 seconds, eliminating the first two options.
Now, a lot of races will have times going into the decimal places (tenths, hundredths, thousandths, etc). With integers however, they are whole numbers, and fractions and decimals are not considered whole numbers. With this info, we can eliminate the last option.
With the other three options eliminated, your answer is C. Real numbers from 0 to 11.
