Question #N552

The first sentence of the passage provides a brief explanation of the topic. The second sentence elaborates on this explanation, providing more specific information about the topic. The third sentence summarizes the key points of the passage. What type of punctuation does the first sentence of the passage need?

The first sentence of this passage needs which of the following punctuation marks?
A. A comma
B. A semicolon
C. A colon
D. A period