I have forgotten my 5-character computer password, but I know that it consists of the letters a, b, c, d, e in some order. When I enter a potential password into the computer, it tells me exactly how many of the letters are in the correct position.
When I enter abcde, it tells me that none of the letters are in the correct position. The same happens when I enter cdbea and eadbc.
Using the best strategy, how many further attempts must I make in order to guarantee that I can deduce the correct password?
ANone: I can deduce it immediately
BOne
CTwo
DThree
EMore than three