What is the Ksp expression for Ni3(PO4)2(s) in water?

options:

Ksp = [Ni2+]3[PO43-]2


Ksp = [Ni2+]2[PO43-]3


Ksp =(3x[Ni2+])(2x[PO43-])


Ksp =(3x[Ni2+])3(2x[PO43-])2