Investment which firms are planning to invest in an economy is known as :

Ex-ante Investment

The correct answer is option (3) : Ex-ante Investment

"Ex-ante" is a Latin term that means "before the event." In the context of economics and investment, "Ex-ante" is used to describe anticipated or planned values before they actually occur. When firms are in the planning stages and are making projections or estimates about their future investments, these are referred to as "Ex-ante Investments!"

1. Ex-ante Investment (Option 3): - "Ex-ante" implies anticipation or planning before an event occurs. - Firms make investment decisions based on their expectations and projections for the future economic conditions.

2. Ex-post Investment : - "Ex-post" means after the event. This term is used to describe actual values or outcomes that occur after an event has taken place. It's more about retrospective analysis, looking at investments that have already been made and assessing their outcomes.