How did American business in the 1920s attempt to solve the problem of developing enormous universal markets for its mass-produced goods?
a. American business developed a large range of product variations.
b. American business nurtured the birth and development of consumer advertising.
c. American business engaged in fierce price-competition wars.
d. American business introduced direct selling through catalogues and door-to-door solicitations.
e. American business offered government-backed guarantees on product performance.