5. The three views of a solid are shown in the figure. The surface area of this solid is A. $3 \pi$ B. $4 \pi$ C. $2 \pi + 4$ D. $3 \pi + 4$ [Figure] 6. ``$\sin \alpha = \cos \alpha$'' is ``$\cos 2 \alpha = 0$'' a A. sufficient but not necessary condition B. necessary but not sufficient condition C. necessary and sufficient condition D. neither sufficient nor necessary condition
5. The three views of a solid are shown in the figure. The surface area of this solid is\\
A. $3 \pi$\\
B. $4 \pi$\\
C. $2 \pi + 4$\\
D. $3 \pi + 4$\\
\includegraphics[max width=\textwidth, alt={}, center]{2127fd6c-54be-499a-a5e1-4b2b0a02c393-1_607_634_1966_230}
6. ``$\sin \alpha = \cos \alpha$'' is ``$\cos 2 \alpha = 0$'' a\\
A. sufficient but not necessary condition\\
B. necessary but not sufficient condition\\
C. necessary and sufficient condition\\
D. neither sufficient nor necessary condition