which one of the following is the same as $$3\times \frac{2}{7}$$? 
选项为:A:$$3\times2\times7$$  B:$$3 \times 2 \times \frac{1}{7}$$  C:$$\frac{2}{7} \times \frac{2}{7} \times \frac{2}{7}$$  D:$$3 \times \frac{2}{7} \times \frac{1}{7}$$  请回答其中一个选项.