Exponential Growth of a Population Is Represented by DN/dt = $\frac { \gamma N } { K }$

Exponential growth of a population is represented by dN/dt =

A) $\frac { \gamma N } { K }$
B) rN
C) rN (K + N)
D) rN $\frac { ( K - N ) } { K }$
E) rN $\frac { ( N - K ) } { K }$