c
\(\begin{array}{l}
Give,\,{u_c} = {u_B} = 0,{a_C} = 4m/{s^2},{a_B} = 2m/{s^2}\\
hence\,relative\,acceleration,\,{a_{CB}} = 2m/{\sec ^2}\\
Now,\,we\,know,\,s = ut + \frac{1}{2}a{t^2}\\
200 = \frac{1}{2} \times 2{t^2}\,\,\,\,u = 0\\
Hence,\,the\,car\,will\,catch\,up\,with\,the\,bus\,after\,time\,\\
t = 10\sqrt {2\,} {\rm{second}}
\end{array}\)
