The consensus among astronomers, based upon observation of the surfaces of pulsars, is that pulsars are spinning ball...

Ravi on July 8, 2019

@Shiyi-Zhang,

Happy to help.

(D) says, "It presents a new finding that challenges the consensus
view of the structure of pulsars."

"New finding" is what allows us to get rid of (D); we do not have any
sort of reason to believe that this is a brand new finding or
discovery, so we can get rid of this choice.

(A) says, "It helps explain how pulsars could have neutrons on their
surface even if they were not entirely made up of neutrons."

(A) helps us to clarify why it'd still make sense for a pulsar to be
filled with quarks if we've observed them with a surface of neutrons.
Thus, (A) is the correct answer choice.

Does this make sense to you? Let us know if you have any other questions!