What work will be done in moving a unit test charge?

Three point charges are on the x axis: q1 = +2 m at x = 0, q2 = +2 mC at x = 3 m and q3 = -4 mC at x = 6 m. What is the work done in moving a unit test charge between the points A(0,2) and B(0,4) on the y-axis?