The correct answer is "Ilmu Ekonomi Mikro". The mechanism of markets is studied in microeconomics, which focuses on individual economic units such as households, firms, and industries. Microeconomics analyzes how these units make decisions regarding the allocation of resources and how their interactions determine prices and quantities in specific markets. It also examines factors that influence individual behavior, such as supply and demand, market equilibrium, consumer preferences, and production costs. Therefore, studying the mechanism of markets falls within the scope of microeconomics.