If it were easy, everyone would do it

Which of these would be the best way to upgrade a 32-bit Windows 7 Professional system to a 64-bit version of Windows 7 Professional?

A) Windows Anytime Upgrade

B) In-place upgrade using the x64 installation media

C) Windows Easy Transfer

D) Windows Upgrade Advisor from the x64 installation media

E) In-place upgrade using the x86 installation media

F) This is why people buy brand new computers