Why is the 17th amendment significant?
a. it upholds the antitrust of the northern securities company.
b. it requires the direct election of us senators by voters.
c. it allowed women to vote.
d. it spelled out illegal practices for businesses.
e. it investigated violations of federal regulations and found unfair ways of competition.

The 17th Amendment is significant because B.  It requires the direct election of US senators by voters.

Here it is in its original form:

The Senate of the United States shall be composed of two Senators from each State, elected by the people thereof, for six years; and each Senator shall have one vote. The electors in each State shall have the qualifications requisite for electors of the most numerous branch of the State legislatures.

When vacancies happen in the representation of any State in the Senate, the executive authority of such State shall issue writs of election to fill such vacancies: Provided, That the legislature of any State may empower the executive thereof to make temporary appointments until the people fill the vacancies by election as the legislature may direct.

This amendment shall not be so construed as to affect the election or term of any Senator chosen before it becomes valid as part of the Constitution.

South carolina was so angry about the election of lincoln that they seceded from the union on december 20, 1860. they attacked fort sumter later, on april 12, 1861.

B. total incorporation