$5.$ Suppose we are sorting an array of eight integers using quicksort, and we have just finished the first partitioning with the array looking like this: $25179121110.$ Which statement is correct?

a$.$ The pivot could be either the $7$ or the $9$

b$.$ The pivot could be the $7,$ but it is not the $9$

c$.$ The pivot is not the $7,$ but it could be the $9$

d$.$ Neither the $7$ nor the $9$ is the pivot.