As a result of the McKinley Tariff in 1890, a.
prices for Hawaiian sugar dropped, and the islands’ economy collapsed.
b.
Hawaiians were able to drive out foreign sugar planters.
c.
Hawaiian sugar was shipped duty-free to the United States for the first time.
d.
Hawaii ceased to be of interest to the United States.

a. prices for Hawaiian sugar dropped, and the islands’ economy collapsed.

Explanation:

Trade can be defined as a process which typically involves the buying and selling of goods and services between a producer and the customers (consumers) at a specific period of time.

Tariffs can be defined as government imposed levies, fees or duties on goods that are imported into or exported out of a country.

Generally, tariffs can reduce both the volume of exports and imports in a country. In order to generate revenues, domestic government make use of tariffs.

The McKinley Tariff was a tariff bill introduced in 1890 by a House of Representatives member from Ohio, United States of America. It was enacted by the United States Congress and signed into law on the 1st of October, 1890. The McKinley Tariff is the highest tariff in the history of USA to date because this Tariff Act of 1890 raised the average import duties on foreign products from 38% to 49.5%, so as to protect all domestic industries from foreign competitors.

Furthermore, the Act removed or eliminated tariffs on tea, hides, molasses, coffee, and sugar with exception to Hawaii. Consequently, opening the American market to sugar from other countries while leading to a decline or collapse of Hawaiian's economy.

As a result of the McKinley Tariff in 1890, prices for Hawaiian sugar dropped, and the islands’ economy collapsed.