During the time of economic recession, it is important to implement measures that can help stimulate the economy. Option 1 suggests that interest rates should be increased. However, this is not generally recommended during a recession as it can make borrowing more expensive and further dampen economic activity. Option 2 suggests that taxes should be increased. While this may help generate additional revenue for the government, it can also have a negative impact on consumer spending and investment, further worsening the recession.

Option 3 states that expenditure on public projects should be increased. This is usually a preferred option during a recession. Increasing public expenditure can help create jobs, boost consumer spending, and revitalize the economy. It can also lead to increased confidence and investment from the private sector. This option aligns with the concept of fiscal stimulus, which involves using government spending to stimulate economic growth.

Option 4 suggests that both interest rates and taxes should be increased. However, this approach can have a contractionary effect on the economy, worsening the recession. It is generally advised to adopt expansionary policies during a recession to encourage economic growth.

In conclusion, the correct answer is option 3 - increasing expenditure on public projects during a time of economic recession.