Cannizzaro reaction involves 

Cannizzaro's reaction is a disproportionation process in which two molecules of an aldehyde combine with a hydroxide base to generate a primary alcohol and a carboxylic acid. In this reaction, one aldehyde is oxidized to give a carboxylic acid whereas the other aldehyde undergoes reduction to yield the alcohol. 

Therefore, the correct answer is option (B) Oxidation as well reduction of aldehyde.