Single dose of drug used in emergency contraception?

Single dose of drug used in emergency contraception ??

Levenorgestrol 1.5gm, 75mg in 2 doses!

Levonorgestrel 1.5mg stat within the first 72 hours

Levonorgestrel 1.5 mg single dose or 0.75 mg in 2 doses 12 hours apart within 72 hours