A Client at 35 Weeks' Gestation Has Begun to Have

A client at 35 weeks' gestation has begun to have contractions.She is diagnosed with preterm labor.Which statement by the nurse best describes the rationale for giving this client magnesium sulfate?

A) "Magnesium sulfate will cause your baby to gain weight quickly so he will be more developed when he is born."
B) "Magnesium sulfate is used to decrease your stress level.This will cause your contractions to stop."
C) "Magnesium sulfate will allow you to be monitored from home."
D) "Magnesium sulfate relaxes your uterus and slows contractions.This gives the baby's lungs a few more days to develop."