A light wave is incident over a plane surface with velocity x. After reflection the velocity becomes :

• A. <table><tr><td rowspan="2"><span style=" text-decoration: overline;"> </span></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>x</center></td><td rowspan="2"></td></tr><tr><td style="text-align: center;">2</td></tr></table>
• B. x
• C. 2x
• D. <table><tr><td rowspan="2"><span style=" text-decoration: overline;"> </span></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>x</center></td><td rowspan="2"></td></tr><tr><td style="text-align: center;">4</td></tr></table>