why oppose a protective tariff?

Tariffs protect manufacturing or agriculture. The logical result of tariffs is "trade wars" which led to the great depression of the 1930s. The US exports lumber products to Canada and imports car parts. The Us Car parts industry wants more business from Detroit so they get congress to raise the tariff on Canadian car parts. So in retaliation, canada raises duties on plywood and they go back and forth on their entire list of imports and exports until both sides quit trading with the other and the surpluses in each country cause plant closings and layoffs which ripple through their economies and those of their other trading partners.

Or a real case: GM want tariffs of 17% on Japanese autos because they are losing US market share to the Japs. Congress raises the tariff. GM responds, not by selling their now lower relative cost cars to Americans and increasing their market share, but by raising their prices a coincidental 17% resulting in higher profits and a huge bonus for the president of GM.

Tariffs create bitter foes.

The Cousins' War," Kevin Phillips, Basic Books, 1999, pp. 378

"...most Northern goods were cheaper [than European goods - ed.] in Mobile or Chattanooga only because of high U.S. tariffs on rival foreign manufacturers. These tariffs, which financed 85 to 90 percent of the operations of the federal government, directly and indirectly fell most heavily on agricultural districts, principally in the South and West. Economists have a phrase for this: internal colonialism."

Daily Chicago Times, December 10, 1860:

"The South has furnished near three-fourths of the entire exports of the country. Last year she furnished seventy-two percent of the whole...we have a tariff that protects our manufacturers from thirty to fifty persent, and enables us to consume large quantities of Southern cotton, and to compete in our whole home market with the skilled labor of Europe. This operates to compel the South to pay an indirect bounty to our skilled labor, of millions annually."

“So the case stands, and under all the passion of the parties and the cries of battle lie the two chief moving causes of the struggle. Union means so many millions (of dollars) a year lost to the South; secession means the loss of the same millions to the North. … the quarrel between North and South is, as it stands, solely a fiscal quarrel.” – Charles Dickens, as editor of All the Year Round, a British periodical in 1862

That was a fiscal quarrel among American brothers that cost over 600,000 dead.

No good has ever come from a tariff.

The bad effects are that the consumer has to pay higher prices for lower quality goods.

Competition is what produces lower prices and higher quality goods - protective tariffs remove competition.

I think a better question would be why shouldn't we have protective tariffs ,our life style is different than a lot of other Country's we need fair trade ,but not free trade, shame on our leadership.

I will go with B as well.