The correct answer is B) protective tariffs.
The other options were A) states' rights. C) the abolition of slavery. D) two-party politics
The option that was a key element of the American System was protective tariffs.
During the 1800s, the American System represented a new style of protectionism of the US economy. It was based on the establishment of new protective tariffs to help the United States industry, federal subsidies to construct basic infrastructures such as roads and the creation of a national bank to impulse trade.