Answer :
Option (d) or (iv) is the correct answer because establishing monopolies and trusts was a tactic or strategy employed by big business owners to boost company earnings throughout the Industrial Age.
Why establishing monopolies and trusts were important during the Industrial age?
Businesses aspired to build monopolies during the late nineteenth and early twentieth century.
A monopoly means a company is the sole manufacturer of a product or has the ability to control industry because it can create far more than its competitors.
For more information about the industrial age, refer below
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