A company has developed a new video game console. After completing cost analysis
and demand forecasts, the company has determined that the profit function for the
new console is p(c) = -250c^2 + 70,000c - 4,570,000, where c is the number of
consoles sold. What is the domain of the profit function?

a. all integers
b. all rational numbers
c. all integers greater than or equal to zero
d. all rational numbers greater than or equal to zero