Identify the reagent ' R ' used in the following reaction.

Ketone $\xrightarrow{\mathbf{R}}$ Semicarbazone

Identify the product in following reaction. Pent -3-enenitrile $\xrightarrow[\mathrm{H}_3 \mathrm{O}^{+}]{\mathrm{AlH}(\mathrm{B}-\mathrm{B})_2}$ product

Identify product 'B' in following reaction

Identify the product obtained when excess of benzoyl chloride is treated with dimethyl cadmium.