The third alternative is correct (C).
Self discipline is a way of avoiding the procrastination of roles and obligations, so as to avoid stress and anxiety by missing out on the deadline. In other words, it is a process of organization and administration of the correct time for the exercise of its activities and for the correction of harmful behaviors.
In this way, creating a routine for homework, restricting the amount of candy eaten, and doing homework always after school are examples of self-discipline. However, doing the home work just before class is a bad sign, as it means that there has not been adequate completion and this is reflected in the time frame. For example, if exercising at home is big or difficult, leaving it to the last minute can cause you not to complete the task. This generates anxiety, stress and problems in your school. This type of problem also extends into adult life. That's why we need to be organized.