The correct option is D 11
We know that the number obtained by adding two numbers of the form "ab+ba" is always divisibe by 11.
ab + ba = (10×a+b) + (10×b + a) = (10+1)×a + (10+1)×b = 11a + 11b
= 11(a+b)⇒ This number is always divisible by 11.
So, option d is correct.