A.Jerry's new job is going well...all in the present tense
c. because answer A is irrelevant because the piece of evidence is about how to count not about rocks. Answer B is also irrelevant because there is no proof that wind-wolf was forced to work instead of helping out. answer D has nothing to do with any of it because the evidence is about counting not that he is unhappy or wants to learn differently.
the answer is D. Some of the world’s highest waterfalls can be found in three countries: Venezuela, South Africa, and Peru.
a colon in a sentence means the auther can end the sentence with a period if he wanted and the sentence would still be correct.
in this case the sentence could be, "Some of the world’s highest waterfalls can be found in three countries."
this still looks and sounds correct and is a fully functioning sentence.