问题如下：
According to the capital market theory, the market portfolio includes all:
选项：
A.risky assets.
B.tradable assets.
C.investable assets.
解释：
A is correct.
The market includes all risky assets, but not all assets are tradable, and not all tradable assets are investable.
the capital market theory，不是应该包括所有risk asset和所有risk-free asset的吗？为什么答案只说包括了risk asset ？谢谢！
