Concept:Purchases account records the total cost of goods bought for resale, whether paid in cash or on credit.Explanation:Capital introduced is not a purchase, so it is ignored.Cash purchase of goods on 12/08 is 10,000.Sale of fixtures on 13/08 is not a purchase.Sale of goods on credit to Lagbaja is income, not a purchase.Credit purchase of goods from Tamedu on 15/08 is 8,000.Therefore, the purchases account balance = cash purchases + credit purchases.This becomes 10,000+8,000=18,000.Answer:₦18,000Option B.