A In a communist system people can work for themselves or a privately owned business - no, this is false: in a communist system, the businesses are owned by the people, all the people own all the businesses together!
B In a communist system individuals and corporations own businesses and property - false, the people collectively own it!
C In a capitalist system business owners who work hard can increase their profits - this is the correct answer!
D In a capitalist system the government decides which goods to produce and sets the price - false, the government does not intervene!