Sensitiveness of a governor is defined as

(a) \(\frac{\text { Range of speed }}{2 \times \text { Mean speed }}\)

(b) \(\frac{2 \times \text { Mean speed }}{\text { Range of speed }}\)

(c) Mean speed \(\times\) Range of speed

(d) \(\frac{\text { Range of speed }}{\text { Mean speed }}\).