Critical Reasoning

Some economists view the Kennedy - Johnson tax cut of 1964, which radically reduced corporate and individual taxes, as the impetus for the substantial prosperity enjoyed by the United States in the late 1960s and early 1970s.

Which of the following, if true, would most weaken the claim that the tax cut of 1964 was the impetus for economic prosperity?

(A) Modernized, more productive factories were built in the late 1960s as a result of the funds made available by the tax cut.

(B) Improved economic conditions in Western Europe and Japan resulted in substantially increased demand for United States manufactured goods in the late 1960s.

(C) The tax cut of 1964 contained regulations concerning tax shelters that prompted investors to transfer their savings to more economically productive investments.

(D) Personal income after taxes rose in the years following 1964.

(E) In the late 1960s, unemployment was relatively low compared with the early 1960s.

OA B

My dilemma:
I was going to choose B but ended up choosing C because B seemed to be out of scope, I need an expert to clarify why B is not OUT OF SCOPE. While C indicates that the tax cut was the indirect reason for the prosperity, so I thought that this would be the next best answer. Please and thanks.[/spoiler]

Unfortunately if you think B is out of scope, it means that you need to spend more time studying weakening questions. According to Powerscore CR Bible, one of the methods to weaken a conclusion is to introduce alternative explanations creating disconnects between premise and conclusion. B does exactly that, and C is actually strengthening by saying that tax cut prompted better investment thus improving the economy.

yeah, I cracked open the Powerscore CR bible again and realized just that.

Thanks for the help.