Critical Reasoning

Critics of sales seminars run by outside consultants point out that since 1987, revenues of vacuum cleaner companies whose employees attended consultant-led seminars were lower than revenues of vacuum cleaner companies whose employees did not attend such seminars. The critics charge that for vacuum cleaner companies, the sales seminars are ill conceived and a waste of money.
Which of the following, if true, is the most effective challenge to the critics of sales seminars?
(A) Those vacuum cleaner companies whose sales were highest prior to 1987 are the only companies that did not send employees to the seminars.
(B) Vacuum cleaner companies that have sent employees to sales seminars since 1987 experienced a greater drop in sales than they had prior to 1987.
(C) The cost of vacuum cleaner sales seminars run by outside consultants has risen dramatically since 1987.
(D) The poor design of vacuum cleaner sales seminars is not the only reason for their ineffectiveness.
(E) Since 1987, sales of vacuum cleaners have risen twenty percent.



Please explain the answer too

Should be E

a) talks about pre 1987 but critics talk about post 1987

b) Support the argument

c) On the whole, doesn't weaken the argument. Cost has increased but was it worth it. Moreover doesn't counter "ill conceived" argument

d) Supports the argument as it agrees that seminar is ineffective but because of reasons other than design

e) If the sales has increased, then the seminar is not ill conceived and a waste of money

I think it's C.

(A) irrelevent, talks about a period prior to 1987.
(B) strengthens the argument.
(C) This is a cost for the company, the revenues are the sales minus the costs, if the seminar costs have increades, then, even if the companies sell more they'll have have less revenue.
(D) strengthens the argument saying that the problem is in the seminars.
(E) strengthens the argument, sales ar up, but why companies that send salesmen to seminars have less revenues.

There might be a flaw in my reasoning, i am assuming that by revenues they mean net income, but i excluded all the rest for the given reasons.
what is the OA?

No,The OA is A
I am looking for a good explanation

(A) The critics are comparing the sales of the higest sales company with those of the companies not doing so well.

Year1: Let's say company A was already making 100K a year and decided to not send its salesppl for the seminar. Year2 sales are still 100K. No improvement

Company B was making 10K a year(year1). After sending its sales folks to the seminar, it started making 50K a year(year2). This is a great improvement of 400% increase in sales(i.e. Revenue). However this is still less than Year2 sales of Company A.

The comparison is illogical. It's not apples to apples anymore. The critics should have chosen to compare the growth in sales instead.

So the answer is A

(B) It weakens the argument
(C) Cost is irrelevant. Profits = Rev - Cost. We are not discussing profits. Only revenues.
(D) We are trying to challenge the critics NOT support them.
(E) Overall increase in sales don't reflect the performance of a particular company's sales team.

I agree with option A.