Mark the letter A, B, C, or D to indicate the sentence that is closest in meaning to each of the following questions.
Carbon dioxide is one of the primary greenhouse gases that cause global warming.
A. Carbon dioxide is the only greenhouse gas that causes global warming.
B. Global warming results in greenhouse gases, including carbon dioxide.
C. One of the main greenhouse gases that lead to global warming is carbon dioxide.
D. Global warming causes greenhouse gases, including carbon dioxide.