BTW, I'm no structural engineer, I could barely spell it in fact, but If I had to guess which had stronger walls, the WTC or the Pentagon, I'd go with B. Pentagon.

Actually you would have guessed wrong lol. The WTC was built like a tube with all the structural bracing on the outside. The facade that gave the buildings their distinctive look were actually practical rather then decorative.

With the Pentagon, the strength was created with internal columns. The outer facade, while having some bracing ability, was not intergral in holding the structure up

The columns within the Pentagon were built well beyond any code existing at the time, or even now. The best way to describe them is super dooper double re-inforced.

This was done for the assumed load bearing they would need to carry. As it turned out the builidng continuing the be used by the Forces mean't structurally the building is being under utilised