Functional isomers of CH3−CH2−CH2−COOH
CH3-CO-O-CH2-CH3
CH3-CH2-CO-O-CH3
H-CO-O-CH-(CH3)2
We know the conditions for functional isomers:
→ Same molecular formula
→ Different functional group
Option (a),(b) and (c) have same molecular fornula as CH3CH2COOH but all three have same functional group
(ester=R-CO-OR').But different CH3−CH2−CH2−COOH
Therefore,
Option (a),(b) and (c) are correct.