tion Consider the following code snippet. What should be placed in the blank to cause a message to be displayed when the user enters the same letter twice in a row? letter = input ("Enter the next...

Extracted text: tion Consider the following code snippet. What should be placed in the blank to cause a message to be displayed when the user enters the same letter twice in a row? letter = input ("Enter the next letter in the alphabet: ") while letter != "": out of previous = letter ove flag letter = input ("Enter the next letter") if print ("Duplicate input") O a. letter == letter O b. alphabet[0] == previous %3D O c. letter == previous O d. alphabet[0] == letter %3D