A level Physics ocr a stress, strain and young modulus

The container has a mass of 2.8 30 lifted by four identical steel cables attached to the container as shown below. Each cattle length 32 m and cross-sectional area 4.5×10m². The container in lifted vertically at a constant velocity. The Young modulus of steel is 2.1×10 Pa

Calculate the extension in mm of each cable.

I'm really confused on how to do the question??? Cananyone please help me?