Step 1: Acute fatty liver of pregnancy (AFLP) is a rare but potentially fatal obstetric emergency caused by microvesicular fatty infiltration of hepatocytes. Step 2: It characteristically presents in the third trimester (and occasionally in the early postpartum period), making 3rd trimester the correct answer. Step 3: The underlying mechanism is a fetal defect in the long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) pathway, leading to accumulation of fatty acid metabolites that damage the maternal liver. Step 4: Risk associations include a male fetus, first (primigravid) pregnancy, multiple gestation, and maternal low body weight. It is uncommon in the first trimester, so option b is wrong, and although postpartum onset can rarely occur, the classic and most common timing is the third trimester rather than the intrapartum window.