586. Prompted by new evidence that the health risk posed by radon gas is far more serious than was previously thought, property owners are being advised by authorities to test all dwellings below the third floor for radon gas and to make repairs as needed.

(A) property owners are being advised by authorities to
(B) property owners are advised by authorities that they should
(C) authorities are advising property owners to
(D) authorities are advising property owners they
(E) authorities’ advice to property owners is they should

Solution:

Modifiers + Idioms + Wordiness/Awkwardness

“Prompted by…” must modify “authorities”. Therefore, the choice starting with “authorites…” must be
the right choice. Hence, A and B are incorrect because, after the coma, they start with “property”, which can’t be modified by “prompted by…”.
In D, “owners they test” is not idiomatic.
In E, “that” is missing after “is” --“advice to…owners is (that) they should…”
Furthermore, E is wordy and awkward.
In C, “owners to test” is idiomatic.
Hence, C is the best choice.

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