A plot is in the shape of a right-angled triangle whose shorter sides measure 78.8 meters and 62.4 meters respectively.

Let opposite = o = 78.8 metres
Let adjascent = a = 62.4 metres
Let hypotenuse = h = ??
Given that an insect covers 100 inches in 1.79 minutes and 1 meter = 39.37 inches
$$o=39.37\cdot78.8=3102.36\approx3102\ inches$$
$$a=39.37\cdot62.4=2456.69\approx2457\ inches$$
$$clo\sin g\ pythagoras,\ h=\sqrt{o^2+a^2}$$
$$\ h=\sqrt{\left(3102\right)^2+\left(2457\right)^2}$$
$$\ h=\sqrt{9622404+6036849}$$
$$\ h=\sqrt{15,659,253}$$
$$\ h=3957.18\approx3957\ inches$$
Perimeter of a triangle = o + a + h
= 3102 + 2457 + 3957
=9516 inches
Insect covers 100 inches in 1.79 minutes
It will cover 9516 inches in t
$$t=\frac{9516\cdot1.79}{100}$$
$$t=170.34\approx170\min utes$$
If it takes 170 minutes to cover the perimeter then it will take 170 minutes to get back to the starting point
Converting 170 minutes to hours:
$$=>\frac{170}{60}=2.83\approx3hours$$
$$Answer\ =\ D$$