17. GWD-26-Q17 Responding to the public’s fascination with-and sometimes undue alarm over-possible threats from asteroids, a scale developed by astronomers rates the likelihood that a particular asteroid or comet may collide with Earth. A. a scale developed by astronomers rates the likelihood that a particular asteroid or comet may B. a scale that astronomers have developed rates how likely it is for a particular asteroid or comet to C. astronomers have developed a scale to rate how likely a particular asteroid or comet will be to D. astronomers have developed a scale for rating the likelihood that a particular asteroid or comet will E. astronomers have developed a scale that rates the likelihood of a particular asteroid or comet that may
Why the given answer is C instead of D For C, "will be to" and "a scale to rate how likely" are wordy; They should be "will" and "a scale to rate the likelihood"
For D, "a scale for rating sth" is OK. I find a lot "a scale for rating" or "a scale to rate" by Google. For example,
The New York Times has developed such a scale for rating the quality of writing in specific stories by its editorial personnel. Astronomers have devised a scale to rate the danger posed by asteroids headed for Earth, comparable to the Richter scale of earthquake fame.