单选题 In a certain conservative mutual fund, 70 percent of the money is invested in bonds, and of that portion, 40 percent is invested in highly rated corporate bonds. If at least $1.4 million in this fund is invested in highly rated corporate bonds, what is the smallest possible total value for the mutual fund?
A. $4 million
B. $5 million
C. $6 million
D. $7 million
E. $8 million

【正确答案】 B

【答案解析】If 40 percent of the amount invested in bonds is invested in highly rated corporate bonds, then the total amount invested in bonds is $1.4 million times 10/4 = $3.5 million. $3.5 million in bonds is 70 percent of the total fund, so the total fund is $3.5 million times 10/7 = $5 million.