Answer :
Answer: Choice C
Explanation:
This is after using the nCr combination formula
[tex]_n C _r = \frac{n!}{r!*(n-r)!}[/tex]
where in this case n = 7 and r = 4. Note how n-r = 7-4 = 3.
We use nCr instead of nPr because the order of the toppings doesn't matter.