June 1997 Digital LR2 8, How to approach Strengthen questions?

Early in the development of a new product line, the critical resource is talent. New marketing ventures require a degree of managerial skill disproportionate to their short-term revenue prospects. Usually, however, talented managers are assigned only to established high-revenue product lines and, as a result, most new marketing ventures fail. Contrary to current practice, the best managers in a company should be assigned to development projects.

Which one of the following, if true, most strengthens the author’s argument?

A   

On average, new ventures under the direction of managers at executive level survive no longer than those managed by lower-ranking managers.

B   

For most established companies, the development of new product lines is a relatively small part of the company’s total expenditure.

C   

The more talented a manager is, the less likely he or she is to be interested in undertaking the development of a new product line.

D   

The current revenue and profitability of an established product line can be maintained even if the company’s best managers are assigned elsewhere.

E   

Early short-term revenue prospects of a new product line are usually a good predictor of how successful a product line will ultimately be.

My Work:
Pre-phrase: There is not another reason why new marking ventures are failing. They are failing because they specifically do not have talented managers.
Conclusion: Contrary to current practice, the best managers in a company should be assigned to development projects.
Premise, What is the evidence to support this?:
• Early in the development of a new product line, the critical resource is talent.
• New marketing ventures require a degree of managerial skill disproportionate to their short-term revenue prospects.
• Usually, however, talented managers are assigned only to established high-revenue product lines and, as a result, most new marketing ventures fail.
Why is this argument flawed?
What if there is another reason as to why these new marketing ventures are failing?

I've read power score's explanation and understand by E is incorrect (the answer I chose) but still confused on how to approach strengthen questions. I focused on the conclusion, "Contrary to current practice, the best managers in a company should be assigned to development projects." and interpreted it as the author wants the best managers on these developmental projects. So the focus of the argument being on developmental projects. And led to my prephrase "the author assumes there is not another reason why new marking ventures are failing" and hunted for answer choices that could fix that problem. Because I thought for Strengthen questions you focus on the conclusion and fill in the gap between the conclusion and premise. So when I read answer D, "The current revenue and profitability of an established product line can be maintained even if the company’s best managers are assigned elsewhere", I thought, "isn't the author focused on success for the developmental projects and not the success of the established projects?". To me It wasn't relevant to their conclusion. Can someone please explain why this is an incorrect way of thinking? also please provide tips on how I can improve my pre-phrasing when it comes to filling gaps in the argument and looking at flaws. I appreciate any help!!