The stimulus only mentions brain size when talking about the spiny anteater—but that's relative brain size, not absolute. We don't know if animals with the smallest brains have relatively small brains, or if they're just overall teeny-tiny.

Even if we did, the stimulus doesn't mention how much sleep is needed to clear out parasitic connections. We don't know how much dream time is needed, or if more sleep equates to more dreams. There's too much missing information for (A) to be supported.

(B) is way too strong to be supported by the stimulus. We can maybe infer that people have fewer accidental associations after (dream-filled) sleep, but we can't say there are "virtually no" such associations. We don't know if dream processes are that effective!

The stimulus tells us dreams let the brain erase connections that would clog our memories. (C) makes a strong inference that the reverse is also true: if we can't dream, our memories will get clogged up, and therefore become impaired.

The stimulus never mentions the content of dreams, so we can't say whether any particular description of a dream would be inaccurate. Dreams might include meaningful connections between ideas, or they might not—neither claim is supported.

The stimulus says the spiny anteater is the only mammal without REM sleep. (E) misrepresents this two ways: it swaps out "mammal" for "animal," and REM sleep for dreaming.

In other words, the stimulus doesn't discuss animals other than mammals. It also doesn't say REM sleep always indicates dreaming, just that it correlates with stronger dreams for humans. So (E) goes too far to be supported.