\( (p) \) represents the total cost to produce \( p \) units of a product. If the domain is restricted to \( 0 \leq p \leq 500 \), what is a reasonable interpretation of this domain?
A. The factory can produce a maximum of 500 units.
B. The profit is maximized when 500 units are sold.
C. The production cost cannot exceed \( \$ 500 \).
D. It takes 500 minutes to produce the units.
4. A graph of a function is increasing on the interval \( (-\infty, 2) \) and decreasing on the interval \( (2, \infty) \). What key feature is located at \( x=2 \) ?
6. A water tank is being drained. The function \( V(m) \) gives the volume of water in gallons after \( m \) minutes. If \( V(10)=500 \) and \( V(20)=200 \), what is the average rate of change from 10 to 20 minutes?
\[
\frac{V(20)-V(10)}{20-10}=\frac{200-500}{20-10}
\]