A General Quadratic Demand Function Has the Form to Follow $q = c p ^ { 2 } + l p + r$

Multiple Choice

A general quadratic demand function has the form to follow. $q = c p ^ { 2 } + l p + r$ (c, l, r are constants, $l \neq 0$ )

Obtain a formula for the elasticity of demand at a unit price p.

A) $E = c p ^ { 2 } + l p + r$
B) $E = - \frac { 2 } { p + r }$
C) $E = - \frac { p ( 2 c p + l ) } { c \mathrm { p } ^ { 2 } + l p + r }$
D) $E = - l p$
E) $E = \frac { c p + l } { c p ^ { 2 } + l p + r }$