$3.)(10$ pt$)$ Write a step$-$wise mechanism for the following transformation. Show electron flow with appropriate arrows.

${?}_{C{H}_{3}OH}^{NaOC{H}_3}$

$4.)(10$ pt$.)$ Reaction of compound $A,$ formula $C_8{H}_{14}O,$ with the Wittig reagent $C{H}_2=P(C_6{H}_5{)}_3$ produces compound $B,C_9{H}_{16}.$ Treatment of compound A with $LiAl{H}_4$ yields two diastereomeric products $C$ and $D,$ both $C_8{H}_{16}O,$ in unequal yields. Heating either $C$ or $D$ with concentrated sulfuric acid produces compound $E,$ with the formula $Cs{H}_{14}.$ Ozonolysis of $E$ produces a keto aldehyde. Oxidation of this keto aldehyde with chromic acid produces:

Provide structures for compounds A through E$.$ Pay particular attention to the stereochemistry.