问题如下：
When it comes to the characteristic of commercial paper, we know that:
选项：
A. It is a type of long-term debt.
B. It is secured debt.
C. It is a low rate debt.
解释：
C is correct.
Commercial paper: short term; unsecured; low rate debt.
前面刚有一道题说到了commercial paper也是一种long term debt？？？不解……
