Choice A rationale False labor contractions, often called Braxton Hicks, are typically irregular and weak, do not increase in intensity or duration over time, and usually cease with walking or changing position. Importantly, false labor does not cause progressive changes in the cervix, meaning the dilation would not progress from 4 cm to 6 cm as described in this clinical scenario. This lack of cervical change differentiates it from true labor. Choice B rationale Placental abruption involves the premature separation of the placenta from the uterine wall, which usually presents with painful, firm, or rigid uterine tone and often vaginal bleeding. While the uterus is firm, the complete softening between contractions and progressive cervical change are classic signs of normal labor, not the sustained, often hypertonic, rigidity associated with a severe abruption. Choice C rationale Uterine tachysystole is defined as more than five contractions in a 10-minute period, averaged over 30 minutes, or a series of single contractions lasting longer than 2 minutes. The scenario describes contractions lasting 45 seconds with complete relaxation between, which is within the normal range for active true labor, and does not meet the criteria for tachysystole. Choice D rationale True labor is characterized by a pattern of regular, strong contractions that lead to progressive effacement and dilation of the cervix. The contractions described, which make the uterus firm, last 45 seconds, and are associated with cervical change from 4 cm to 6 cm, fit the criteria for active true labor.