A prepositional phrase has to start with a preposition, and the only option here which starts with one is D, 'during the darkest night', where 'during' is a preposition.
Answer:
The International Astronomical Union (IAU) downgraded the status of Pluto to that of a dwarf planet because it did not meet the three criteria the IAU uses to define a full-sized planet. Essentially Pluto meets all the criteria except one—it “has not cleared its neighboring region of other objects."
Explanation:
You did not provide the excerpt but I wound it and the correct answers are the following two sentences:
1.<span>For once, at least, I grasped the mental operations of the Morlocks.
Here we see that they do possess a kind of intelligence, maybe at first strange and unclear but it is there, no matter how strange it might seem.
2.</span><span>I was surprised to find it had been carefully oiled and cleaned.
Here the Time Traveler has found his Time Machine and he finds that the Morlocks had tried to grasp its function and its purpose. They have taken it apart and then cleaned and oiled it, which suggests they know somethings about how the machine work.
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