James received a report from the production and purchasing departments with the following values for january: actual materials quantity: 90,000 pounds total actual cost: $47,200 standard materials quantity: 5.5 pounds/unit standard price: $0.55/pound units made: 16,300 two days later, he got a correction report from the purchasing department that they found another invoice for $6,200. how much would james’ materials price variance change for the month of january?

a : $3,900 f
b : $3,900 u
c : $6,200 u
d : $6,200 f