Explanation:

- Market Price is the price that consumers pay for goods and services. It's the amount on the price tag.

- Factor Cost is the cost of resources used up in creating a product. This includes wages, rent, and profits, but excludes taxes and subsidies.

- The difference between market price and factor cost is mainly due to taxes and subsidies.

- Option 1: Direct taxes are levied directly on income and wealth. These don't impact the difference between market price and factor cost directly.

- Option 2: Indirect taxes are taxes like VAT or sales tax, added to the price of a product. These typically increase the market price.

- Option 3: Subsidies are amounts paid by the government to reduce the cost of goods for the consumer, lowering the market price.

- Option 4: Net indirect taxes is the correct answer. It's the total of indirect taxes minus subsidies that affect the difference between market price and factor cost.