An insect trapped in a circular groove of radius 12 cm moves along the groove steadily and completes 7 revolution in 100 s. The linear speed of the insect is

• A

  4.3 $\mathrm{cm} {\mathrm{s}}^{-1}$

• B

  5.3 $\mathrm{cm} {\mathrm{s}}^{-1}$

• C

  6.3 $\mathrm{cm} {\mathrm{s}}^{-1}$

• D

  7.3 $\mathrm{cm} {\mathrm{s}}^{-1}$