A \( C H_{3} C H_{2} B r + N a \overset{e t h e r}{\to} C H_{3} - C H_{3} + N a B r \)
B \( C H_{3} C H_{2} B r + N a C l \overset{a l c h o h o l}{\to} C H_{3} - C H_{2} C l + N a B r \)
C \( 2 C H_{3} B r + 2 N a \overset{a l c h o h o l}{\to} C H_{3} - C H_{3} + 2 N a B r \)
D \( 2 C H_{3} C H_{2} B r + 2 N a \overset{e t h e r}{\to} C H_{3} - C H_{2} - C H_{2} - C H_{3} + 2 N a B r \)