What's the probability C with a superscript of 0 and a subscript of 4?

What's the probability C with a superscript of 0 and a subscript of 4?

The probability C has a superscript of 0 and a subscript of 4 for 1
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C(4,0)=C(4,4)=4*3*2*1/(1*2*3*4)=1
The superscript of probability C is 0, and the subscript of probability C is 4, and the subscript of probability C is 4