Explanation:

- An open economy incorporates trade with other countries, which affects Aggregate Demand (AD).

- Option 1: Only involves private consumption. It doesn't reflect other components like investment, government spending, or trade.

- Option 2: Involves household investments only. It leaves out consumption, government spending, and net exports.

- Option 3: Includes government and private consumption spending. However, it omits investment and net exports.

- Option 4: Encompasses household consumption, investment, government spending, and net exports. This accurately reflects AD in an open economy, as it includes all crucial components.