Texto associado.  Question must be answered based on the following text.  
This passage from “The Sign of the Four” by Arthur Conan Doyle, captures Holmes’ logical approach to deduction and showcases his analytical abilities.
 "When you have eliminated the impossible, whatever remains, however improbable, must be the truth", said Sherlock Holmes. 
Available at: https://standardebooks.org/ebooks/arthur-conan-doyle/the-sign-of-the-four/text/single-page#chapter-6
 Study the sentence: "When you have eliminated the impossible, whatever remains, however improbable,
must be the truth", said Sherlock Holmes. Choose the option in which the Indirect Speech is used correctly.
  ✂️         a) Sherlock Holmes explains that when he has eliminated the impossible, whatever remains, no matter
how improbable, must be the truth.      ✂️         b) Sherlock Holmes explained that when one had eliminated the impossible, whatever remained, no
matter how improbable, must be the truth.      ✂️         c) Sherlock Holmes explained that when you had eliminated the impossible, whatever had remained, no
matter how improbable, must have been the truth.      ✂️         d) Sherlock Holmes explained that when you have eliminated the impossible, whatever has remained, no
matter how improbable, must have been the truth.