First identified in 1969, komatiites are Earth’s oldest known

The direct answer to your question is no, the passage is not saying that temperatures this high cannot exist (quite the opposite, in fact). But what's more important is that we weren't asked "what does the passage say?" Let's take a closer look at the question:

"Organization" is another word for "structure," and this passage is structured into two paragraphs. So why does the author write each of these two paragraphs?

• Paragraph 1 introduces komatiites and presents a hypothesis for how they formed (i.e., from the hottest lava ever known).
• Paragraph 2 presents the work of two geologists who had previously tried to explain how volcanic rocks like komatiites could be created. The author uses their research to support the statement that "the discovery of komatiites changed geologists’ assumptions about the characteristics of the Earth’s mantle around the time of the formation of komatiites, between 2.5 and 4 billion years ago."

To recap: P1 tells us about komatiites, and P2 explains why the discovery of komatiites mattered. Let's see which answer choice matches our understanding of how the passage is organized.

This choice only describes paragraph 2, which is enough reason to eliminate it. But if we take this further, the choice falls apart because the author never reconciles the views of Bowen and Hess. Ultimately, Bowen is shown to be right and Hess is shown to be wrong.

This is a pretty good match! The "phenomenon" is komatiites (more specifically, the way in which komatiites are formed). The first paragraph certainly was written to describe komatiites, and the second paragraph discusses how and why komatiites were scientifically significant. Let's keep (B) around and see if we find anything that's even better.

Which portion of the passage traces the discovery of komatiites? Paragraph 1 mentions the discovery, and paragraph 2 walks through research that took place prior to the discovery of komatiites. But neither paragraph traces how komatiites were discovered.

Futhermore, paragraph 2 focuses on research that was done before komatiites were discovered, and nothing in the passage discusses implications for further research. Choice (C) looks good at first, but falls apart completely once you start reading it closely. Let's eliminate it.

Komatiites are the only things we might call "recently discovered" in this passage. But the author begins paragraph 2 by telling us that the discovery of komatiites "was surprising in light of then-current geological theories." This directly contradicts choice (D), so we'll eliminate (D) as well.

This passage only details one way in which komatiites are exceptional: their high magnesium content. And the author is focused on explaining how high magnesium content became part of the komatiites, not classifying various exceptional details. This choice doesn't line up with the structure of the passage, and doesn't accurately describe what the author is doing. Eliminate (E).

(B) is the only answer choice that lines up with what we've actually read, so we're sticking with it. I hope this helps!