let us simplify the argument --
Just as many tasks are uncompleted, phone calls unreturned ... before "busyness" --> People are not that busy as they claimThis option is based on the fact that "same number" of tasks are uncompleted. From this the author draws the conclusion that people are not that busy. One immediate weakness that we can point out is --
What if people before "busyness" had fewer number of tasks to be completed? I.e. the people today have many more tasks to do. The number of incomplete tasks would then only be a small percentage of the total number of tasks today but a larger proportion of the tasks before "busyness".
We have been asked to weaken the conclusion -- "people are not as busy as they claim". We need an answer option that supports "people are indeed busy".
Let us look at the answer options--
Option A - IncorrectThis actually strengthens the conclusion. If "looking busy" is a status symbol, then people might pretend to be busy even though they really are not busy.
Option B - Correct answerthis agrees with the line of reasoning mentioned above. If people have much more to do, then it is quite natural that few of them would not be completed. But since this "few" is equal to the number of tasks that were incomplete before "busyness" outbreak, we can safely say that people today get many more tasks done. Hence, more busy.
Option C - IncorrectIf people spend a lot of time talking about "being busy", then probably they are not as they busy as they claim to be. Strengthens the conclusion.
Option D - IncorrectIf the number tasks completed is the same (and also the number of tasks that are incomplete), we can safely say that people are not more busy. Strengthens the conclusion.
Option E - IncorrectAlso strengthens the argument.