What does the “two and twenty” fee structure refer to?

a. Hedge fund fee structure with a fixed management fee equal to 2% of AUM and 20% incentive fee for all profits above the benchmark made by the hedge fund

b. Hedge fund fee structure with a management fee equal to 2% of AUM for every 20% AUM increase made by the hedge fund

c. Hedge fund fee structure with a flexible management fee varying from 2% to 20% of AUM depending on the fund’s performance

d. Hedge fund fee structure with a fixed management fee equal to 2.20% of AUM