SOLUTION:Hint: In Main point questions, you have to rephrase the conclusion.
Conclusion: some organizations have engineered out all the slack they can from their businesses at the expense of agility.
(A) Business should be flexible enough to change as and when they want
INCORRECT. It is pretty much rephrasing the premise.
(B) Those organizations that are not very efficient can adapt to change very well.
INCORRECT. This is not what the paragraph says. The paragraph argues against super-efficiency in organizations. But to say that lack of slack can reduce flexibility is not the same as saying that an organization has to be inefficient to adapt to change “well”.
(C) Business processes without slack will slow down an organization’s progress.
INCORRECT. This sentence talks of business processes without slack “slowing down” an organization’s “progress”. The paragraph given doesn’t talk of organizational “progress”. In fact, it argues against cutting down slack in order to increase speed and efficiency.
(D) Reducing slack to zero can cost businesses their adaptability to change.
CORRECT. This paragraph argues that organizations that engineer out all the slack from their businesses in order to become super-efficient do so at the expense of their flexibility and adaptability to change. Option (D) sums up this idea well.
(E) Too little slack in organizations is as bad for innovation as too much slack.
INCORRECT. This option can also be ruled out, as it brings in a new idea: innovation. The paragraph only mentions flexibility, agility and ability of organizations to meet expectations that can change at the drop of a hat.