How should the morning after pill be taken?

• A. two OCP each containing ethinyl oestradiol 50micrograms within 12 hours of sexual intercourse and two more taken at 72 hours post sexual intercourse
• B. two such pills taken as a single dose within 72 hours of sexual intercourse
• C. two such pills taken within 72 hours of sexual intercourse and two more taken twelve hours later
• D. two pills taken at twelve hours post sexual intercourse and two more taken 72 hours later
• E. two pills taken with 12 hours of sexual intercourse does not require a second dose