Expected change in Vitamin B12 deficiency -

Ans. is 'b' i.e., Increased methylmalonic acid in urine Isomerization of methylmalonyl CoA to succinyl CoAo In this reaction, the active form of vitamin B12 is deoxyadenosyl cobalamine.o Propionyl-CoA is produced as the catabolic end product of some aliphatic amino acids and b-oxidation of odd chain fatty acids.o Propionyl CoA is then converted to succinyl CoA through methyl malonyl-CoA.o Thus methylmalonyl-CoA is accumulated and excreted in urine as methylmalonic acid (methylmalonate) in vitamin B12 deficiency, i.e. methylmalonic aciduria.