Right option is (c) cotɸ – cotα = c/b
Explanation: The condition for correct steering is that all the four wheels must turn about the same instantaneous centre.
The fundamental equation for correct steering is
cotɸ – cotα = c/b
where ɸ and α = Angle through which the axix of the outer wheel and inner wheel turns respectively
c = Distance between the pivots of the front axles
b = Wheel base.