​An example of moral hazard is

A) ​people drive less carefully in icy conditions with antilock brakes than without
B) people drive as safely with more airbags as without
C) football players avoid 'spearing' with their heads even with safer helmets
D) ​people read the medicine warnings as carefully when self-medicating as with a doctor's prescription

The theory of education that states firms use educational attainment as a way of sorting between high-ability and low-ability workers is called