Southern planters objected to the protective tariff of 1816 because it: decreased the selling price of cotton increased the price of skilled slaves increased the cost of manufactured goods pay for western improvements

Increased the cost of manufactured goods.

Explanation:

A tariff is a tax on an imported good. Tariffs have been used several times throughout American history in order to promote the interests of American businesses. This is due to the fact that tariffs increase the price  of foreign goods. This increase in the price of foreign goods results in Americans being more likely to buy goods in the US (as they are usually cheaper after the tariff is added in).

Southerners hated tariffs at this time because a majority of their manufactured goods came from other countries. Since the tariff was added to goods coming in from places like Great Britain and France, it increased the price of manufactured goods. This made Southerners angry.

b. parliament was weaker than the monarchy.