Which of the following were methods used by labor unions to secure better working conditions?

collective bargaining
piecework
strikes

strikes

Explanation:

The labor movement in the United States grew out of the need to protect the common interest of workers.  

To get their demands, the unions rely on various strategies, like strikes:

Workers refuse to return to work until their demands are fulfilled. The company comes to a standstill and consent to granting the union's demands.

i am pretty sure the awsers is d.

i do not know if this question has options, but a main impact of the federal reserve act of 1913, which created the federal reserve bank, was the international use of the u.s. dollar, which soon became the world's leading currency - particularly during world war i, since many nations around the world asked the united states for money.