In the figure below, the set pressure of the relief valve is 5MPa, the set pressure of the pressure reducing valve is 2.5MPa, and the piston area of the cylinder is 50cm 2 . When the load is 0kN, 7.5kN and 30kN, please answer the following questions: (1) Could the hydraulic cylinder be pushed? (2) What is the pressure value of point A, B and C?