How did a pool differ from a trust?
a. pools were larger than trusts.
b. a trust limited competition, but a pool did not.
c. only vertically integrated companies formed pools.
d. pools were made of independent companies, but a trust was not.

The correct answer is d.Pools were made of independent companies, but a trust was not. Basically, pools are made to prevent companies from entering each other's turf. Trusts are made to dictate the market and the prices and build monopolies. Pools are therefore better than trusts because trusts want to harm the consumer for higher profit.