​One of the solutions to the adverse selection problem in insurance is

A) ​Is to require that only the high risk individuals to buy insurance
B) Is to require that only the low risk individuals buy insurance
C) Is to require everyone to buy insurance
D) ​Is to completely ban insurance companies

Requiring everyone to buy insurance helps to balance out the risk pool and prevent adverse selection. If only high-risk individuals are required to buy insurance, then premiums may become too expensive for them to afford, leading to further adverse selection. Alternatively, if only low-risk individuals are required to buy insurance, then insurance companies may not have enough revenue to cover the losses of high-risk individuals. By requiring everyone to buy insurance, the risk pool becomes more diverse and premiums can be set at a level that covers losses across the whole population.