Optically active alkyl bromide $A(C_8{H}_{17}Br)$ reactions with potassium tert$-$butoxide in tert$-$

butanol to yield compound $B(C_8{H}_{16}).$ Compound $B$ affords the carbonyl compound shown

below and formaldehyde when subjected to ozonolysis followed by a reductive workup. Write

the reactions and draw the structures of $A$&$B.$