Why isnt't "remove all problems" a good answer?

[Carla Louse]

English Idioms and Expressions, Advanced Level

ESL/EFL Test #13 "Squeaky Clean", question 5

With the appointment of a new director it was decided to make a clean sweep and create a new board of governors.

(a) remove all obstacles
(b) remove all chairs
(c) remove all symbols
(d) remove all problems

English Idioms and Expressions, Advanced Level

ESL/EFL Test #13 "Squeaky Clean", answer 5

With the appointment of a new director it was decided to remove all obstacles and create a new board of governors.

Correct answer: (a) remove all obstacles

Your answer was: incorrect
With the appointment of a new director it was decided to remove all problems and create a new board of governors.
_________________________

Why isnt't "remove all problems" a good answer?

Carla Louse

[Yankee]

.
Actually, (d) remove all problems seems just as good an answer as (if not better than) (a) remove all obstacles.

Here is a dictionary definition for "make a clean sweep":

Remove or eliminate unwanted persons or things, as in "The new owners made a clean sweep of the place, intending to replace all the equipment." This phrase replaced the much older (16th-century) general sweep. [Mid-1800s]

http://dictionary.reference.com/search?q=make%20a%20clean%20sweep