Astronomer Mark Holland and colleagues examined four white dwarfs-small, dense remnants of past stars-in order to determine the composition of exoplanets that used to orbit those stars. Studying wavelengths of light in the white dwarf atmospheres, the team reported that traces of elements such as lithium and sodium support the presence of exoplanets with continental crusts similar to Earth's.

Question

Text 2
Past studies of white dwarf atmospheres have concluded that certain exoplanets had continental crusts. Geologist Keith Putirka and astronomer Siyi Xu argue that those studies unduly emphasize atmospheric traces of lithium and other individual elements as signifiers of the types of rock found on Earth. The studies don't adequately account for different minerals made up of various ratios of those elements, and the possibility of rock types not found on Earth that contain those minerals.
Based on the texts, how would Putirka and Xu (Text 2) most likely characterize the conclusion presented in Text 1?
A) As unexpected, because it was widely believed at the time that white dwarf exoplanets lack continental crusts
B)
As premature, because researchers have only just begun trying to determine what kinds of crusts white dwarf exoplanets had
C) As questionable, because it rests on an incomplete consideration of potential sources of the elements detected in white dwarf atmospheres
D) As puzzling, because it's unusual to successfully detect lithium and sodium when analyzing wavelengths of light in white dwarf atmospheres

Answer 1

C) As questionable, because it rests on an incomplete consideration of potential sources of the elements detected in white dwarf atmospheres