Total annual expenditure of the family = 4 × 13750 + 3 × 11750 + 5 × 31750 = 2,49,000
Annual savings of the family = Rs. 15,550
∴ Total annual income of the family = 2,49,000 + 15,550 = Rs. 2,64,550
⇒ Average monthly income = 2,64,550/12 = Rs. 22,045
Hence, option (b).