In the reaction MgCl2 + 2KOH Mg(OH)2 + 2KCl, if 3 moles MgCl2 are added to 4 moles KOH, what determines how much Mg(OH)2 is made?
A. The amount of MgCl2 + KOH
B. The amount of KCl
C. The amount of MgCl2
D. The amount of KOH