I realized these were trick questions at #5. My answers till then were "well, on gcc on i686, probably ____". The trick questions are in poor taste imo.
I had my formative C experience in the DOS era with 16-bit compilers and then SGIs with 64-bit compilers (and I had the "fun" of porting grad student written code from SGI to Linux) so you get burned with expectations about int length. Packing makes it even worse as many RISC machines (like MIPS) are word addressed and non-aligned loads require a bunch of bit fiddling or you get a Bus Error (SIGBUS).