The correct option is E All I, II and III
From III, we have: Rajan's basic salary = Rs. 1550.
From I, we have: Vasu's basic salary = Rs. (1550 + 100) = Rs. 1650.
From II, we have: Rajan's other allowances = Rs. 2000 and Vasu's other allowances = Rs. 2050.
Therefore Vasu's monthly salary = Rs. (1650 + 2050) = Rs. 3700.