Answer
(b) and (d) are logistic differential equations.
Work Step by Step
Comparing with the standard equation of a logistic differential equation
$$
\frac{d y}{d t}=k y\left(1-\frac{y}{A}\right)
$$ we see that
(a) it is not a logistic differential equation.
(b) it is a logistic differential equation with $k=2$ and $A=3$.
(c) it is not a logistic differential equation.
(d) it is a logistic differential equation with $k=2$ and $A=1/3$.
