Two expressions are shown below. Which of the following is the DIFFERENCE obtained when subtracting expression II from expression I?
I. y2−4xz+z2
II. x2+xz+2y2


A. −y2−5xz+z2−x2

B. 3y2−3xz+z2−x2

C. 3y2−3xz+z2+x2

D. y2+5xz−z2+x2