To calculate the gross profit, we need to subtract the cost of goods sold (COGS) from the total revenue (sales).
COGS represents the cost of the products that were sold during the period, and it is calculated as:
COGS = Opening stock + Purchases - Closing stock
In this case, the values are:
COGS = ₦20,000 + ₦70,000 - ₦15,000 = ₦75,000
Total revenue (sales) is given as ₦100,000.
Therefore, the gross profit can be calculated as:
Gross profit = Total revenue - COGS = ₦100,000 - ₦75,000 = ₦25,000
Hence, the answer is option (D) ₦25,000.