What practice allows businesses in a capitalist system to drive others out of business?
a)competition
b)monopolizing
c)lowering price
d)all of the above

The practice which allows businesses in a capitalist system to drive others out of business would be d - all of the above.

Indeed, all of the mentioned strategies are effective in driving out the competition when the people/company desire this to happen. 

The transcontinental railroad provided a means of fast transportation. it cut a 6 month trip into 6 days, created jobs for many people and encouraged immigration. the homestead act played a huge role in western expansion; it allowed settlers to begin a fresh start, and gave them land in exchange for their residence for up to five years and a small fee.