An optically active, pure, four carbon containing saturated alcohol $\mathrm{X}$, when reacted with $\mathrm{NaH}$ followed by ${\mathrm{CH}}_3-\mathrm{I}$ gives a compound $\mathrm{M}$. Same alcohol $\left(\mathrm{X}\right)$ when treated with $\mathrm{TsCl}$ followed by sodium methoxide gives $\mathrm{M}\text{'}. \mathrm{M}$ and $\mathrm{M}\text{'}$ are