Correct option is C
We use formula
For 2(1/2) years, A = P[1 + (R/100)]2 × [1 + (R/200)]
CI = A - P
Where, Amount = A, Principal = P, Compound Interest = CI
According to the question
A = 36000 × [1 + (10/100)]2 × [1 + (10/200)
A = 36000 × (11/10) × (11/10) × (21/20)
A = 36000 × (121/100) × (21/20)
A = 18 × 121 × 21 = Rs. 45,738
Now, CI = A - P
= 45,738 – 36000 = Rs. 9,738