Answer:
C. Say's Law and Quantity Theory of Money.
Explanation:
The Classical economics supports the idea of law and quantity theory of money. The Classical economist believe that economy is capable to achieve its natural level of real GDP (Gross Domestic Product). The real GDP is obtained when the country's available resources are used to its fullest. Classical theory focuses on monetary policy to manage its money supply in an economy and focuses on fiscal policy to manage aggregate demand.