One example of foreign aid is a. economic sanctions b. military training c. low tariffs d. free trade.

The correct answer is D) Free trade.

Economic sanctions are a form of punishment. This is why this answer choice can not be correct, as it is the opposite of aid.

A tariff is a tax on an imported good. This would not be considered foreign aid, as tariffs actually increase the price of foreign goods. This shows why the third answer is incorrect.

Military training is not an example of foreign aid cause aid implies that this is helping a country's economy. Military training does not necessarily help a country's economy.

This is why letter D is correct.