$\"\"$

The differential equation is $\"\"$ .

The differential equation $\"\"$ is positve for any values of $\"\"$ and $\"\"$ .

$\"\"$

Observe the graph,

The slope of the tangent line(shown in red color) is negative, hence $\"\"$ is negative.

Thus, the graph does not indicates the solution of the differential equation.

$\"\"$

(b)

$\"\"$

Substitute $\"\"$ in $\"\"$ .

$\"\"$

Thus, slope is zero.

Slope of the function is zero when the maxima and minima at the point where slope of the function is zero.

Observe the graph,

At $\"\"$ slope of the graph is not equal to zero, since no maxima or minima exist at $\"\"$ .

Thus, the graph does not indicates the solution of the differential equation.

$\"\"$

Neihter of the graphs indicate the solution of the differential equation.