Read the sentence and answer the question. Apollo astronauts took additional classes astronomy, Earth geology, life sciences, and geology of the Moon. Which correctly shows where a colon is needed in the sentence? A. Apollo astronauts took additional classes: astronomy, Earth geology, life sciences, and geology of the Moon. B. Apollo astronauts took: additional classes astronomy, Earth geology, life sciences, and geology of the Moon. C. Apollo astronauts took additional classes astronomy, Earth geology, life sciences: and geology of the Moon. D. Apollo astronauts took additional classes astronomy: Earth geology, life sciences, and geology of the Moon.