Answer: $90
Explanation: closing stock as at November ending is 3, consisting of:
1 DVD bought on 1st June @ $47
1 DVD bought on 1st Nov @ $43
1 DVD bought on 30th Nov @ $36
using FIFO (First in first Out) inventory method, 2 of the DVD was sold as at the end of December.
Cost of goods sold in the month of December is $47 +$43 = $90