The correct answer is - a. command economy.
The communist and socialist political systems have the tendency to create a command type of economy in the countries where they are on power. The command economy is an economy type where the government is controlling everything, production, manufacturing, possession of resources, planing, organizing, and the private sector is usually nonexistent. This type of economy mainly focuses on self-sufficiency, but as the history had shown so far it fails, more often than not.
This type of economy had been used in Yugoslavia, the USSR, China, Libya, Cuba, North Korea.