​An indication that Insurance companies anticipate adverse selection is

A) ​they do not require a deductible
B) they do not classify clients into different risk types according to their claim history
C) they classify clients into different risk types according to pre-existing conditions
D) ​they do not require a co-payment

Insurers classify clients into different risk types according to pre-existing conditions in order to anticipate adverse selection, which is when individuals with higher risk are more likely to purchase insurance. By classifying clients based on their pre-existing conditions, insurers can adjust their premiums accordingly and reduce the likelihood of adverse selection. The other choices (A, B, and D) do not necessarily indicate that insurers are anticipating adverse selection.