The summary of this argument is as follows:
the snake scares away the skipper insect --> snake takes the nest and uses the nest for its own purposes --> When the snakes don't have access to this nest, they wander around in search of other nests.
The conclusion: the snakes don't know how to build their own nest. To strengthen this conclusion, we need an answer choice that proves that the Lichtenstein night adder snake exhibits the same behavior (of always depending on other animal's nests) consistently.
Now, let's take a look at the available answer choices:
A.
Many sub-species of the adder are known to make their own nests from scratch. - this answer choice is incorrect because the passage talks only about the Lichtenstein night adder snakes, not about any other snake (sub)species. We need to stick close to the information that's clearly provided in the prompt.
B.
In the summer months, the Lichtenstein night adder snake prefers sleeping by hanging from a tree and not staying anywhere on the ground level. - How does the Lichtenstein night adder's sleeping pattern prove that they can't build their own nests? (B) therefore is irrelevant. Eliminate (B)
C.
In Nigram and Tenitol, countries where Silver-spotted Skippers are not found, the Lichtenstein night adder makes its home in the nests of Cicada insects. -
Okay. Now, this proves that the Lichtenstein night adder snake exhibits the same behavior (of using nests made by other animals). This is what we are looking for. Hence, (C) is the right answer.
D.
The two species of snakes that are closely related to the Lichtenstein night adder species do not live in nests at all. - The passage is only concerned about the Lichtenstein night adder snake, not any other species of snakes. Hence, (D) is irrelevant.
E.
There are no significant differences between the nest of a Silver-spotted Skipper insect and that of some species of adder snakes that make nests of their own. - we are concerned with the idea that the Lichtenstein night adder snake is using other's nests. Nowhere in the passage is the idea of nest quality even mentioned. So, (E) does not strengthen the conclusion