<prompt> True about significant variable decelerations is:Drop in fetal heart rate to less than 90 bpm for 60 secondsDrop in fetal heart rate to less than 100 bpm for 60 secondsDrop in fetal heart rate to less than 80 bpm for 60 secondsDrop in fetal heart rate to less than 70 bpm for 60 seconds  <response>: Ans. is d, i.e. Drop in fetal heart rate to less than 70 bpm for 60 seconds Classification of variable decelerationDecelerationDefinitionMild variable deceleration80 bpm irrespective of duration, or 30 seconds irrespective of depth or between FHR-70 to 80 bpm lasting for 60 secondsModerate variable deceleration70 bpm lasting for 30 to 60 seconds or between FHR-70 to 80 bpm lasting for 60 secondsSevere variable deceleration 70 bpm lasting for 60 seconds 