问题如下：
Your client asking you to creat a portfolio which could provide a minimum return level of 5.2%, because he needs to pay room rental and medical fee without invading the initial capital. The following table shows three alternative allocations, then which one should be used?
选项：
A. Allocation A
B. Allocation B
C. Allocation C
解释：
B is correct. The threshold return level RL for the client is 5.2%,
allocation A: (7.1-5,2)/8=0.2375
allocation B:(8.2-5.2)/9.6=0.3125
allocation C:(10-5.2)/19=0.2526
Acording to the above calculate, allocation B has the highest safety-first ratio.
请问这题知识点在什么地方？