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?