Final answer:
The concept of excess in Act I leads characters to indulge in vices and extravagance, which negatively affects their moral and social behaviors.
Step-by-step explanation:
In Act I of the play, the concept of excess relates to the characters' behaviors by causing them to indulge in vices and extravagance. This excess can lead to a variety of negative outcomes, including a decline in moral standards, the development of harmful habits, and the deterioration of societal values. The provided references indicate that individuals become virtuous or fall into vice depending on their actions, and that excessive indulgence can lead to moral decay and criticism, as seen in the behaviors of certain characters in the play. Furthermore, the quotes imply that identifying with one's own virtues or focusing too much on personal gain can have a detracting effect on character and community. The correct answer to the student's question is (c) It causes them to indulge in vices and extravagance.