Digital Dynamics Inc. has provided the following data for its first three months of operations:

Month	Sales Revenue (£)	Purchases (£)	Operating Expenses (£)	Closing Inventory (£)
Jan	100,000	70,000	30,000	15,000
Feb	110,000	75,000	35,000	18,000
Mar	120,000	80,000	40,000	20,000

Requirements:

1. Calculate the Cost of Goods Sold (COGS) for each month.
2. Determine the Gross Profit for each month.
3. Prepare a quarterly income statement for the three months ended 31 March.