Jean Uses a Calendar to Keep Track of Her Menstrual

Jean uses a calendar to keep track of her menstrual cycle.Using the calendar,she identifies her fertile "window" and refrains from sexual intercourse on those days.Which of the following methods of contraception is Jean using?

A) Cervical barrier method
B) Basal Body Temperature Method.
C) Standard Days Method
D) Hormonal method
E) TwoDay Method