Answer: c. Ask him to talk to people twice a day.
Sociability refers to the ability a person has to "be sociable," or to interact well with other people. People who lack this skill are often called "introverts." Sociability is a very valued skill among humans as we are a species that relies heavily on cooperation among members of a group. A person can improve his or her sociable skills by trying to interact with others frequently and in different settings.