Blood banks in Southern California and Texas have done studies to evaluate how often blood containing Trypansoma cruzi is found in their blood donor pool. They have found that the incidence varies between 1:8,000 to 1:40,000 donors. If you were making up a list of questions to ask blood donors, which of the following questions would be least helpful in screening to exclude this organism from persons that have grown up in an endemic area? A. Have you ever been bitten by a reduvid bug? B. Have you ever eaten pigs, dogs, or other animals that are reservoir hosts for Chaga's disease? C. Have you lived in an adobe hut with a thatched roof? D. Have you ever had swelling of your eye that lasted more than 3 days? E. Have you ever had a blood test positive for Chaga's disease?