Which of the Following Is the Action of Oral Contraceptives

Which of the following is the action of oral contraceptives?

A) To increase the acidity of vaginal secretions, thus acting as a spermicidal
B) To prevent fertilization from occurring by slowing the release of the ovum from the ovary
C) To inhibit ovulation by suppressing FSH and LH levels
D) To decrease the lumen of the fallopian tubes making fertilization more difficult