The correct option is C Extraterrestrial technology would develop at roughly the same rate as human technology.
"Fermi's argument maintains that it is extremely unlikely that many other civilizations discovered science at exactly the same time we did. Had they acquired science even a thousand years earlier than we, they now could be so much more advanced that they would already be colonizing our solar system." - this statement from the first passage implies that the basic assumption Fermi Paradox makes is that extraterrestrial technology would develop at the same rate as our technology has. Assuming that extraterrestrial technology would develop at the same rate as human technology, Fermi's argument maintains the above quoted claim. Thus C is the best answer.