The conjunction that should fill in the blank in this sentence is the
word OR. So, you can retake the test tomorrow or you can do some
extra-credit work, These types of conjunctions, called correlative
conjunctions, always go in pairs, such as either-or, neither-nor, not
only-but also, etc. So, the conjunction is used to show that a person
has to choose between these two things. Nor cannot be used because it is
a negative conjunction. But and and do not fit here.
