问题如下：
Suppose an index consisting of identical securities and weights. If securities included in index are not dividend-paying or interest-bearing,the difference between a price return index and a total return index will be:
选项：
A.grater than 0.
B.less than 0.
C.equal to 0.
解释：
The difference between the price return index and the total return index, which is composed of the same securities and weights, is due to the income generated from underlying securities over time. If the securities in the index do not have income, the values of both indices are the same.
这道题可以请讲解下吗，对应哪个知识点，具体是什么意思
