Given \(\theta=\) angle through which the axis of the outer forward wheel turns

\(\phi=\) angle through which the axis of the inner forward wheel turns

\(a=\) distance between the pivots of front axle, and

\(b=\) wheel base.

For correct steering, centre lines of the axes of four wheels of an automobile should meet at a common point. This condition will be satisfied if

(a) \(\cos \theta-\cos \phi=a / b\)

(b) \(\cot \theta-\cot \phi=a / b\)

(c) \(\cos \theta+\cos \phi=a / b\)

(d) \(\tan \theta+\tan \phi=b / a\).