Ans: A
$\begin{array}{rcl}
\text{The $1$st expression} & = & x^3y^2z^2 \\
\text{The $2$nd expression} & = & x^3y^3z^5 \\
\text{The $3$rd expression} & = & x^ay^bz^c \\ \hline
\text{HCF} & = & x^2y^2z \\
\text{LCM} & = & x^3y^4z^5
\end{array}$
Consider the variable $x$. Since HCF takes the lowest power among the three expressions, then $a=2$.
Consider the variable $y$. Since LCM takes the highest power among the three expressions, then $b=4$.
Consider the variable $z$. Since HCF takes the lowest power among the three expressions, then $c=1$.
Therefore, the $3$rd expression is $x^2y^4z$.
