Monetary policy refers to the actions taken by a central bank or monetary authority of a country to achieve its macroeconomic objectives. It involves various measures to control the supply of money and credit in the economy. The correct option is 'C' - credit control.

Credit control measures are the most important instruments of monetary policy to regulate the economy's credit creation capacity. The central bank uses various tools to control the supply of money and credit in the economy, which include:

1. Reserve Requirements: The central bank sets a minimum reserve requirement for banks, which they have to maintain with the central bank. By changing the reserve requirement, the central bank can influence the amount of money and credit that banks can create.

2. Open Market Operations: The central bank buys or sells government securities in the open market to influence the supply of money and credit in the economy.

3. Discount Rate: The central bank sets a discount rate at which it lends money to commercial banks. By changing the discount rate, the central bank can influence the cost of borrowing for banks and, hence, the supply of credit.

4. Moral Suasion: The central bank can use moral suasion to persuade banks to follow its policies voluntarily.

The main objective of credit control measures is to regulate the supply of money and credit in the economy to achieve macroeconomic stability. Some of the macroeconomic objectives of monetary policy include:

- Price stability: The central bank aims to maintain stable prices by controlling inflation.

- Full Employment: The central bank aims to achieve full employment by influencing the level of economic activity.

- Economic Growth: The central bank aims to promote economic growth by ensuring adequate credit availability to businesses.

Therefore, monetary policy includes credit control measures to regulate the supply of money and credit in the economy to achieve macroeconomic stability.