Which of the following compounds is least likely to give effervescence of $\mathrm{CO}_2$ in presence of aq. $\mathrm{NaHCO}_3 ?$

Match the List I with List II.

Choose the correct answer from the options given below:

The first transition series metal ' $M$ ' has the highest enthalpy of atomisation in its series. One of its aquated ion $\left(\mathrm{M}^{\mathrm{n}+}\right)$ exists in green colour. The nature of the oxide formed by the above $\mathrm{M}^{\mathrm{n}+}$ ion is:

The number of valence electrons present in the metal among $\mathrm{Cr}, \mathrm{Co}, \mathrm{Fe}$ and Ni which has the lowest enthalpy of atomisation is :