Marketing consultant: Last year I predicted that LRG's latest advertising campaign would be unpopular with customers and ineffective in promoting new products. But LRG ignored my predictions and took the advice of a competing consultant. This season's sales figures show that sales are down and LRG's new products are selling especially poorly. Thus, the advertising campaign was ill conceived.
The marketing consultant's reasoning is most vulnerable to criticism on the grounds that
it takes for granted that LRG's sales would not have been lower still in the absence of the competitor's advertising campaign
It’s unclear whether the ad campaign was created by the “competing consultant.” Even if it was the competitor’s campaign and the consultant did assume this, (A) fails to point out that LRG’s low sales might have been caused by something other than the campaign.
it fails to consider that economic factors unrelated to the advertising campaign may have caused LRG's low sales figures
The consultant fails to consider that LRG’s low sales might have been caused by something other than the ad campaign, like economic changes.
it takes for granted that in LRG's industry, new products should outsell established products
The consultant points out that LRG’s new products are selling especially poorly this year, but he never assumes that the new products should outsell older, more established products. Even if he did, (C) doesn’t address the fact that something else might have caused the low sales.
it takes for granted that the higher sales of established products are due to effective advertising
The consultant points out that new product sales are especially low, but he never makes any assumptions about why established product sales are higher. Instead, he assumes that low sales overall are due to the ineffective ad campaign.
it confuses a condition necessary for increasing product sales with a condition that will ensure increased sales
This is the cookie-cutter flaw of confusing sufficient and necessary conditions. The consultant doesn’t make this mistake; his argument relies on causal logic, not conditional logic.