Final answer:
An amniocentesis at 36 weeks gestation with preeclampsia is performed to assess fetal lung maturity, which is important if early delivery is considered due to maternal conditions.
Step-by-step explanation:
The rationale for an amniocentesis performed on a woman at 36 weeks gestation with preeclampsia is a) To assess fetal lung maturity. This procedure involves the extraction of amniotic fluid, which contains fetal cells that can be analyzed to provide information about the baby's genetic health and development. At this stage of gestation, it's crucial to understand the fetal lung readiness for birth, especially if early delivery is being considered due to maternal conditions such as preeclampsia.