A length of 10 mm diameter steel wire is coiled to a close coiled 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
(a) K (b) 1.25 K
(c) 1.56 K (d) 1.95 K