Rory tells a person that he wants to be a psychologist, and the person makes an assumption about his career goals. the person would be least apt to assume that rory will become a(n) psychologist, based on the frequency with which people enter the different subfields of psychology.

The person would be least apt to assume that Rory will become a "health" psychologist, based on the frequency with which people enter the different subfields of psychology.

Health psychologists take part in a wide range of assignments identified with wellbeing and health. The particular sort of work that a health psychologist does once a day may rely upon work setting or claim to fame territory. Numerous health psychologists work specifically in clinical settings to encourage people or gatherings counteract sickness and advance solid practices. Others direct research on health related issues or impact open approach on medicinal services issues.  

a would be the answer