Answer:k=4593.75
Step-by-step explanation:
Given
length of spring =20 cm
maximum compression in spring is x=8 cm
mass of mug m=300 gm
maximum height to which cup is needed to raise is h=5 m
By conserving Energy i.e. Elastic Potential Energy will be converted in to Potential energy of cup

where



so we should use a spring with spring constant k=4593.75 N/m