单选题 In a certain box, there are 3 times as many red balls as blue balls. Which of the following is the ratio of the number of red balls to the number of blue balls?
【正确答案】 C
【答案解析】题目中红球数目是蓝球数目的3倍，那么红球对蓝球数目的比是3：1，选择C。