The correct answer is: A. Duepit.
Duepit was the first economist to propose the idea of consumer saving. He argued that consumers save money in order to provide for their future needs. This idea has been widely accepted by economists, and it is now one of the fundamental principles of economic theory.
Marshall was an English economist who is considered to be one of the founders of neoclassical economics. He developed a theory of consumer behavior that is based on the idea that consumers maximize their utility. Hicks was an English economist who is considered to be one of the founders of modern macroeconomics. He developed a theory of consumer behavior that is based on the idea that consumers optimize their consumption.
Neither Marshall nor Hicks proposed the idea of consumer saving.