Which of the Following Is an Example of Product Differentiation

Which of the following is an example of product differentiation?

A) A marketer searching for unique groups of people whose needs could be addressed through more specialized products
B) Manufacturers of electric heating appliances using advertising to slow the demand for their products
C) Marketers engaged in manipulating the supply of consumer goods to create artificial demand
D) An automobile manufacturer trying to lower the cost of production by manufacturing a small number of cars during lean periods
E) A manufacturer of cosmetics trying to portray that its brands are not only different from its competitors but also superior in terms of quality and variety