The imaginary angular velocity of the earth for which the effective acceleration due to gravity at the equator shall be zero is equal to [AMU 2012J (Take, g = 10 $m{s}^{-2}$ for the acceleration due to gravity, if the earth were at rest, radius of earth equal to 6400 km and  $\lambda$ = 60)

• A

  1.25 x ${10}^{-3}$ rad $s^{-1}$

• B

  2.50 x ${10}^{-3}$ rad$s^{-1}$

• C

  3.75 X ${10}^{-3}$ rad$s^{-1}$

• D

  5 X ${10}^{-3}$ rad $s^{-1}$