Answer:
A) explain why only one of several mass extinctions has received coverage in the popular media
Step-by-step explanation:
The author acknowledges that there are reasons why the four mass extinctions preceding the End-Cretaceous “are invisible, for the most part, in the public imagination.” He then goes on to explain these reasons by citing the dinosaurs, which he defines with a modifying phrase (“the most charismatic characters in the fossil record”). It is this charisma that has made the End-Cretaceous extinction famous and allowed the dinosaurs to “hog most of the popular press spared for paleontology.” Thus the modifying phrase helps to specify or limit the reasons for the dinosaurs’ high media profile. In doing so, it advances the author’s larger argument by explaining why attention to the causes of mass extinction has been given only to the cause of the End-Cretaceous extinction (asteroids) rather than to the changes in climate and geology that were likely responsible for other mass extinctions.