A ray hits the y-axis making an angle \[\theta \] with y-axis as shown in the figure. The variation of refractive index with x-coordinate is \[\mu ={{\mu }_{0}}\left( 1-\frac{x}{d} \right)\] for \[0\le \times \le d\left( 1-\frac{1}{{{\mu }_{0}}} \right)\] and \[\mu ={{\mu }_{0}}\] for \[x

• A. \[d(1-\sin \theta )\]
• B. \[d(1-\cos \theta )\]
• C. \[d\,\,\sin \theta \]
• D. \[d\,\,\cos \theta \]