单选题 An analyst does research about investment return. If an investment earns 0.9% per month, the number of months it will take for the investment to triple in value is closest to:
A. 13
B. 77
C. 123

【正确答案】 C
【答案解析】[解析] (1+0.9%)n=3，两边取Ln，计算出n=123。