In an atomic reactor and an atomic bomb,the multiplication factor $(r)$ per fission is respectively:

• A
  $r = 1$ in an atomic reactor and $r > 1$ in an atomic bomb
• B
  $r > 1$ in an atomic reactor and $r = 1$ in an atomic bomb
• C
  $r < 1$ in an atomic reactor and $r > 1$ in an atomic bomb
• D
  $r = 1$ in an atomic reactor and $r < 1$ in an atomic bomb