The most suitable reagent for the following conversion, is:

(i) Na/ Liquid ${\text{NH}}_3$ (Birch reduction) it reduces non-terminal alkynes into alkene (trans/anti addition)

(ii) ${\mathrm{H}}_2/\mathrm{P}\mathrm{d}-\mathrm{C},$ quinoline (lindlar catalyst) reduces alkyne into alkene by syn addition. This will give the required product.

(iii) $\mathrm{Z}\mathrm{n}/\mathrm{H}\mathrm{C}\mathrm{l}$ is Clemmensen reduction which reduced carbonyl into an alkene.

(iv) $\mathrm{H}{\mathrm{g}}^{+2}/{\mathrm{H}}^{\oplus },{\mathrm{H}}_2\mathrm{O}$ is an electrophilic addition reaction, which converts alkyne into ketone.