Let $N$ be a 50 digit number. All the digits except the 26th one from the right are 1. If $N$ is divisible by 13, then the unknown digit is (a) 1 . (B) 3 . (C) 7 . (D) 9 .
Let $N$ be a 50 digit number. All the digits except the 26th one from the right are 1. If $N$ is divisible by 13, then the unknown digit is\\
(a) 1 .\\
(B) 3 .\\
(C) 7 .\\
(D) 9 .