As a first step in determining
a student’s grade point average, the points for each course letter grade are
multiplied by the credit value of the course to determine the student’s total
points.

The points for each letter
grade are as follows:

Letter Grade Points

A 4

B 3

C 2

D 1

F 0

If each of Stephanie’s five
courses is worth one credit each and she has a total of 13 points, what
combinations of letter grades could she have?