The correct option is B 700
We have to find Rem (777777.... 1001 times)/(1001)
Now, we know that 1001=7×11×13
Clearly, 7777.... 1001 times is divisible by 7. now checking for 11
and 13, we get the form 11k+1 = 13l+9 => 11k - 13l = 8
for k =9 and l = 7, the above equation satisfies, hence the remainder when 777777......is divided by 1001 is 7*(11k+1) => 7*(100) = 700