If you had to choose between the following two options which would you choose and why?

Option A

A single 60 MB .NET Framework Redist Installation package that installs on all 32 and 64 bit platforms.

Option B

A 20 MB .NET Framework Redist that installs on x86
A 40 MB .NET Framework Redist that installs on IA64
A 40 MB .NET Framework Redist that installs on AMD64

I'm curious as to what people think about this and why each option is preferable.