Which of the following has NOT been proposed as a model to explain the origin of modern Homo ...

Which of the following has NOT been proposed as a model to explain the origin of modern Homo sapiens?
 
  a. An origin in Africa followed by migration to other areas where indigenous premodern populations were replaced
  b. An origin in Africa followed by migration to other areas where both interbreeding and replacement occurred
  c. Several origins in different areas where modern forms evolved from local populations
  d. Separate origins in Africa and Australia with migrations from both these areas to displace all other populations
  e. Neandertals and Denisovans mix having given rise to H. sapiens