c
\(\begin{array}{l}
\,\,\,\,\,\,\,\,\,From\,question,\\
\,\,\,\,\,\,\,\,\,Horizontal\,velocity\,\left( {initial} \right),\\
\,\,\,\,\,\,\,\,\,{u_x} = \frac{{40}}{2} = 20m/s\\
\,\,\,\,\,\,\,\,\,Vertical\,velocity\,\left( {initial} \right),\\
\,\,\,\,\,\,\,\,\,\,50 = {u_y}t + \frac{1}{2}g{t^2}\\
 \Rightarrow \,{u_y} \times 2 + \frac{1}{2}\left( { - 10} \right) \times 4\\
or,\,50 = 2{u_y} - 20
\end{array}\)

\(\begin{array}{l}
or,\,\,{u_y} = \frac{{70}}{2} = 35m/s\\
\therefore \,\tan \,\theta  = \frac{{{u_y}}}{{{u_x}}} = \frac{{35}}{{20}} = \frac{7}{4}\\
 \Rightarrow \,\,Angle\,\theta {\tan ^{ - 1}}\frac{7}{4}
\end{array}\)