What Information Is Displayed by an Isoquant

What information is displayed by an isoquant?

A) the whole set of technically efficient factor combinations that can produce varying levels of output
B) various levels of output that can be produced with different factor combinations
C) various levels of output that can be produced with a fixed factor combination
D) the whole set of technically efficient factor combinations that can produce a single level of output
E) the alternative factor combinations that require the same expenditure