Use row operations to solve the system.

x + y - z= -9

4x - y + z= 9

x - 3y + 2z= 7

Select the correct choice below and, if necessary, fill in the answer boxes to complete your choice.

A) This system has exactly one solution. The solution is (__, __, __)

B) This system as infinity many solutions of the form (__, __, z) where z is any real number.

C) This system has no solution.