mental accounting是什么意思？

问题如下：

Based on the description of how Kai manages his finances as outlined in Exhibit 1, Kai most likely exhibits the behavioral bias of:

选项：

A.endowment. B.mental accounting. C.framing.

解释：

Kai has segregated money into four different accounts based on the sources and uses of his funds. Although intuitively appealing, this approach is irrational because money is fungible across the four accounts. Nothing is stopping Kai from collapsing them into a single “account” with a holistic portfolio strategy.