Explanation:

- Let's break it down:

- Monthly income to saving ratio of A is 5:2. Thus, if income = 5x, savings = 2x.

- Expenditure is income minus savings, so monthly expenditure = 5x - 2x = 3x.

- Annual expenditure is Rs.108000, which implies monthly expenditure = Rs.9000 (since 108000 ÷ 12).

- So, 3x = 9000 implies x = 3000.

- Therefore, income = 5x = 15000, and savings = 2x = 6000.

- Now, calculate changes:

- Income increases by 20%: New income = 15000 + 20% of 15000 = 18000.

- Savings increase by 10%: New savings = 6000 + 10% of 6000 = 6600.

- New expenditure = 18000 - 6600 = 11400.

- Percentage increase in expenditure:

- Increase = New expenditure - Old expenditure = 11400 - 9000 = 2400.

- Percentage increase = (2400 / 9000) × 100 = 80/3%.

- The correct answer is Option: 4, 80/3%.