The work of a student to solve a set of equations is shown:

Equation A: y = 4 − 2z

Equation B: 4y = 2 − 4z

Step 1: −4(y) = −4(4 − 2z) [Equation A is multiplied by −4.]

4y = 2 − 4z [Equation B]

Step 2: −4y = 4 − 2z [Equation A in Step 1 is simplified.]

4y = 2 − 4z [Equation B]

Step 3: 0 = 6 − 6z [Equations in Step 2 are added.]

Step 4: 6z = 6

Step 5: z = 1

In which step did the student first make an error?

Step 1

Step 3

Step 4

Step 2