A mixture of cis and trans isomers is obtained by dissolving trans-5-bromo-2-methylcyclohexanone in aqueous NaOH. Show the mechanism of this isomerization. 

Draw the deuterated product of the reaction given below.

The aldol reaction is stereospecific and proceeds via the Zimmerman–Traxler transition state depicted below.

(a) Illustrate the arrow-pushing mechanism for step A and step B.

(b) Explain why this mechanism is favorable.