Which of the following equations depicts Verhulst-Pearl logistic population growth?

• A
  $\frac{dN}{dt} = rN \left( \frac{K-N}{K} \right)$
• B
  $\frac{dN}{dt} = rN \left( \frac{K}{K-N} \right)$
• C
  $\frac{dN}{dt} = rN \left( \frac{K-N}{N} \right)$
• D
  $\frac{dN}{dt} = rN \left( \frac{K+N}{K} \right)$