Answer: 8.
Step-by-step explanation: There are 4 sizes, so let's say that the sizes are small, medium, large, and extra large. There are 2 flavors, so let's say that the flavors are chocolate and vanilla. The possible combinations are below:
As you can see, there are 8 possible combinations that she can choose from as far as 4 sizes and 2 flavors go.
Have a great day! :)