g suppose you received these bit strings over a communications link, where the last bit is a parity check bit. in which string are you sure there is an error? a) 00000111111 b) 10101010101 c) 11111100000 d) 10111101111

String (d) contains an error.What is string ?Traditionally, in computer programming, a string is a sequence of characters as a type of literal constant or variable. In the latter, you can modify its element to change its length or modify it.CalculationDivision algorithm Let aa be an integer and dd a positive integer. Then there are unique integers qq and rr with 0\leq r<d0≤r<d such that a=dq+ra=dq+rqq is called the \textbf{quotient}quotient and rr is called the \textbf{remainder}remainderq=a\textbf{ div }dq=a div dr=a\textbf{ mod }dr=a mod dThe parity check bit is:x_{n+1}=x_1+x_2+....+x_n\textbf{ mod }2x n+1​=x 1​ +x 2​ +....+x n​mod 2(a) The last digit is 1 (which is the parity check bit). We then need to check that the sum of all other digits is equal to the parity check bit modulo 2.\begin{align*} x_{n+1}&=x_1+x_2+....+x_n\textbf{ mod }2 \\ &=0+0+0+0+0+1+1+1+1+1\textbf{ mod }2 \\ &=5\textbf{ mod }2 \\ &=1 \end{align*}x n+1=x 1​ +x 2​ +....+x n​mod 2=0+0+0+0+0+1+1+1+1+1 mod 2=5 mod 2=1​The sum modulo 2 is equal to the parity check bit, thus there does not appear to be an error in the string. The last digit is 1 (which is the parity check bit). We then need to check that the sum of all other digits is equal to the parity check bit modulo 2.\begin{align*} x_{n+1}&=x_1+x_2+....+x_n\textbf{ mod }2 \\ &=1+0+1+0+1+0+1+0+1+0\textbf{ mod }2 \\ &=5\textbf{ mod }2 \\ &=1 \end{align*}x n+1​=x 1 +x 2​ +....+x n​  mod 2=1+0+1+0+1+0+1+0+1+0 mod 2=5 mod 2=1The sum modulo 2 is equal to the parity check bit, thus there does not appear to be an error in the string.(c) The last digit is 0 (which is the parity check bit). We then need to check that the sum of all other digits is equal to the parity check bit modulo 2.\begin{align*} x_{n+1}&=x_1+x_2+....+x_n\textbf{ mod }2 \\ &=1+1+1+1+1+1+0+0+0+0\textbf{ mod }2 \\ &=6\textbf{ mod }2 \\ &=0 \end{align*}xn+1=x 1​ +x 2​ +....+x n​ mod 2=1+1+1+1+1+1+0+0+0+0 mod 2=6 mod 2=0​The sum modulo 2 is equal to the parity check bit, thus there does not appear to be an error in the string.(d) (a) The last digit is 1 (which is the parity check bit). We then need to check that the sum of all other digits is equal to the parity check bit modulo 2.\begin{align*} x_{n+1}&=x_1+x_2+....+x_n\textbf{ mod }2 \\ &=1+0+1+1+1+1+0+1+1+1\textbf{ mod }2 \\ &=8\textbf{ mod }2 \\ &=0 \end{align*}x n+1​=x 1​ +x 2​ +....+x n​  mod 2=1+0+1+1+1+1+0+1+1+1 mod 2=8 mod 2=0​The sum modulo 2 is not equal to the parity check bit, thus there is an error in the string.String (d) contains an error.learn more about strings here :brainly.com/question/4087119#SPJ4