what is true about african architecture?
all of the above
there were no permanent structures built until the 1400s.
no pyramids are found outside of egypt.
african architecture relies on available materials.

Of the provided statements, the true statement is that African architecture relies on available materials. There were many, many permanent structures in Africa prior to the 1400s; for example, Egyptians had been building permanent structures in the region for thousands of years. One example of that are the pyramids; however, pyramids can be found all over the world from Central Asia to Mesoamerica. The only true statement is the one quoted above.