In which sentence are all words spelled correctly?

In which sentence are all words spelled correctly?
 a. Because she knew the new techneque would be more advantageous than the old one, the manager agreed to schedule time for everyone to learn the new method.
  b. Because she knew the new technique would be more advantageous than the old one, the manager agreed to schedule time for everyone to learn the new method.
  c. Because she knew the new technique would be more advantagous than the old one, the manager agreed to schedule time for everyone to learn the new method.
  d. Because she knew the new technique would be more advantageous than the old one, the manager agreed to shedule time for everyone to learn the new method.