A car is travelling with linear velocity v on a circular road of radius r. If it is increasing its speed at the rate of ' a' meter/sec², then the resultant acceleration will be

• A

  $\sqrt{\left\{\frac{v^2}{r^2}-a^2\right\}}$

• B

  $\sqrt{\left\{\frac{v^4}{r^2}+a^2\right\}}$

• C

  $\sqrt{\left\{\frac{v^4}{r^2}-a^2\right\}}$

• D

  $\sqrt{\left\{\frac{v^2}{r^2}+a^2\right\}}$