To solve this problem, we need to understand the conditions for a balanced Wheatstone bridge.$\\$In a Wheatstone bridge, the bridge is balanced when:$\\ \frac{P}{Q} = \frac{X}{Y} \\$For precise measurement of $X,$ the bridge should be as sensitive as possible.$\\$The sensitivity of the bridge is maximized when the resistances are equal or nearly equal.$\\$This means $P \approx Q \approx X \approx Y. \\$When $P$ and $Q$ are approximately equal and small, the bridge is most sensitive.$\\$This is because the change in the galvanometer reading is most noticeable for small changes in $X. \\$Therefore, for the most precise measurement of $X,$ the resistances $P$ and $Q$ should be approximately equal and small.$\\$This corresponds to Option 2.