Solve the system analytically. If the equations are dependent, write the solution set in terms of the variable z. 3x + 6y-z 7 x +y+ 3z = 6 Select the correct choice below and, if necessary, fill in any answer boxes to complete your choice. O A. There is one solution. The solution set is { .): (Simplify your answers.) O B. The system has infinitely many solutions. The solution set is { 2)}, where z is any real number. (Simplify your answers. Use integers or fractions for any numbers in the expressions.) O C. The solution set is .