Solve the Problem $4 p^{2}+q^{2}=1400$ , Where $p$ Is the Price Per Unit in Dollars And

Multiple Choice

Solve the problem.
-The demand equation for a certain product is $4 p^{2}+q^{2}=1400$ , where $p$ is the price per unit in dollars and $q$ is the number of units demanded. Find $d p / d q$ .

A) $d p / d q=-p / 4 q$
B) $d p / d q=-q / 4 p$
C) $d p / d q=-4 p / q$
D) $d p / d q=-4 q / p$