In CRC if the data unit is 100111001 and the divisor is 1011 then what is dividend at the receiver?
Given $CRC$ of the data unit is $100111001$ and divisor is $1011$.
So dividend at the receiver=100111001011
Option B is correct.
How did you subtracted 1011 from 1001 a ? 1011>1001... and what happened with the carry?