The given combination is:
[tex]_9C_4[/tex]Combinations are given by the following formula:
[tex]_nC_r=\frac{n!}{r!(n-r)!}[/tex]Where n is the size of the set and r is the subset size. In this case, n=9 and r=4, let's replace these values and solve:
[tex]\begin{gathered} _9C_4=\frac{9!}{4!(9-4)!} \\ _9C_4=\frac{9!}{4!*5!} \\ \\ _9C_4=\frac{362880}{24*120} \\ \\ _9C_4=\frac{362880}{2880} \\ \\ _9C_4=126 \end{gathered}[/tex]The answer is A. 126
