Answer: c. decreases by $60 million
Explanation:
The formula for Gross Domestic Product (GDP) in a closed economy using the Expenditure method is;
GDP = Consumption + Government Spending + Investment
Therefore;
Investment = GDP - Consumption - Government Spending
GDP remained the same = $0
Consumption fell by $10 million = -$10 million
Investment = 0 - (-10) - 70
Investment = - $60 million