NaBH4 → reduce carbonyl (C=O) into alcohol
Step 1: treatment with NaBH4
Add curved arrows for the first step, Treat Na+ as a spectator ion.
Step 2: treatment with D2ODDNaON
Add curved arrows for the second step. Do not show Na+ counter ion.
Draw the products of the last step (hint: one organic and one inorganic species), including all nonbonding electron pairs.