Element 'A' is 'd' block as well as transition element of $3$d series it is used to convert vegetable oil in to vegetable ghee, (X) is poisonous gas which is used for the extraction of element 'A'. Which option is incorrect.

The transition metal which is used in hydrogenation of oil is nickel. It is used as a catalyst in the hydrogenation of Nickel, therefore element A is nickel (Ni). The poisonous gas which is used in the extraction of metal is carbon monoxide (CO). Therefore, X is CO.

$\underset{\mathrm{A} \left(\mathrm{impure}\right)}{\mathrm{Ni}}+\underset{\mathrm{X}}{4\mathrm{CO}}\to \underset{\mathrm{Volatile} \mathrm{compound} \left(\mathrm{Z}\right)}{\mathrm{Ni}{\left(\mathrm{CO}\right)}_4}\stackrel{∆}{\to }\underset{\mathrm{pure}}{\mathrm{Ni}}+4\mathrm{CO}$

Carbon monoxide burns with a blue flame and produced carbon dioxide on oxidation which is used in photosynthesis.

$\mathrm{CO}\stackrel{\left[\mathrm{O}\right]}{\to }{\mathrm{CO}}_2$

When Ni reacts with CO, it forms Ni(CO)₄ which is volatile compound. It is sp³ hybridized and is a diamagnetic because CO is a strong ligand which results in the pairing of electrons in Nickel. For diamagnetic compound, the value of  $\mu$ is 0.