Too strong. The author never suggests Lamarck’s thoery has been “proven correct.” The author merely describes Steele’s hypothesis for a mechanism that could allow Lamarck’s theory to be correct. But the author never suggests Steele’s hypothesis is actually correct.

Not supported, because the author calls Steele’s hypothesis about how changes in the immune system can be passed to offspring “speculative.” Moreover, the author also does not indicate that a similar mechanism is unlikely to operate elsewhere in the body. Since (C) is unsupported, it can’t be the main point.

This doesn’t capture the author’s emphasis. Although it’s true that the author believes Steele’s hypothesis is speculative and that it relies on circumstantial evidence, the author’s main point isn’t to convey the speculative, unproven aspect of his hypothesis. Rather, the author’s main point is that Steele has a particular hypothesis. In any case, (D) is unsupported, too, because we’re not told that the standard theory of evolution does not rest on purely circumstantial evidence. In fact, even the standard theory of evolution must rest on circumstantial evidence, too, just as Steele’s hypothesis does.

Not supported, because the author never suggests Steele has actually shown that RNA can revert back into DNA. This is part of Steele’s hypothesis, but it hasn’t been proven yet. Since (E) isn’t supported, it can’t be the main point.