Step 1: Concept Grignard reagents react with anhydrous cadmium chloride to form dialkyl cadmium, which further reacts with acyl halides to form ketones.
Step 2: Meaning Methyl magnesium bromide ($CH_3MgBr$) reacts with $CdCl_2$ to form dimethyl cadmium ($(CH_3)_2Cd$) as product 'A'.
Step 3: Analysis Product 'A' ($(CH_3)_2Cd$) reacts with acetyl chloride ($CH_3COCl$) to replace the chlorine atom with a methyl group.
Step 4: Conclusion The reaction $2CH_3COCl + (CH_3)_2Cd \rightarrow 2CH_3COCH_3 + CdCl_2$ yields acetone, which is also known as propanone.
Final Answer: (B)