A length of 10 mm diameter steel wire is coiled to a close helical spring having 8 coils of 75 mm mean diameter, and the spring has a stiffness K. If the same length of wire is coiled to 10 coils of 60 mm mean diameter, then the spring stiffness will be
1
K
2
1.25 K
3
1.56 K
4
1.95 K