The premises don’t match, because we’re not told that frogs from the island are found only in the lagoon. There could be many frogs that live on Scrag Island but not in the lagoon.

The premises don’t match, becaue we’re not told that the owls eat only frogs on the island. Although the owls do eat frogs on the island, they can also eat many other animals, too, including ones that live outside the lagoon, so we don’t have any reason to think they may “never” eat an animal that lives outside the lagoon.

The premises don’t match, because we’re not told that the frogs live only in the lagoon. Although frogs are the only animals known to live in the lagoon, that doesn’t imply the frogs don’t live anywhere else. There might be no other animals besides frogs in the lagoon, but the frogs could live all over the island.

The premises establish that all known X (frogs on Scrag Island) is found in Y (the lagoon), and that Z (owls) eat only X (frogs on Scrag Island). The conclusion asserts that Z (owls) is unlikely to ever eat something that isn’t in Y (the lagoon).

The conclusion is too strong; the argument in the stimulus concludes only that something was “unlikely.” It had to use this language because one of the premises involved only what has been known to be true, which isn’t the same as an assertion that something is in fact true. (E), however, concludes that the owls will definitely not eat anything that lives outside the lagoon. It doesn’t match the language of something being unlikely or likely.