A is the correct answer

Cold environment is a precipitating factor for painful sickle cell crises. Other precipitating factors include heavy physical exertion, dehydration, and stress. Patients should be counseled to avoid these situations when possible. Patients with sickle cell anemia who are pregnant are at an increased risk of morbidity and mortality due to the underlying hemolytic anemia and multiorgan dysfunction associated with sickle cell anemia. Due to the increased turnover of red blood cells, pregnant patients with sickle cell anemia should be prescribed 4 mg of folic acid per day.

Consumption of sugar (B) has not been shown to precipitate a sickle cell crisis. Mild physical exertion (C) should not precipitate a crisis, but heavy exertion can. Overhydration (D) will not precipitate a crisis, but dehydration can.