First we have to find how many bits will be required in sign magnitude representation
512<637<1024
$-2^{N-1}-1 to 2^{N-1}-1$
So n=11 bits here
now we represent 637 in binary format
01001111101 now to represent number in negative we change MSB to 1
So sign Magnitude representation= 11001111101 =1661
So unless there is mistake in question or options none of the options are correct