Which of the following is associated with an increased incidence of heterotopic pregnancy?

A heterotopic pregnancy is more likely associated with any of the following: Conception achieved by Assisted reproductive techniques Persistent or rising hCG levels after dilatation and curettage for an induced or spontaneous aboion A uterine fundus larger than menstrual dates More than one corpus luteum Absent vaginal bleeding in the presence of signs and symptoms of an ectopic pregnancy Sonographic evidence of uterine and extrauterine pregnancy.