How did the royal road benefit the persians? it prevented invaders from entering the persian empire. it encouraged the building of persian naval vessels. it established communication throughout the persian empire. it the persians reach rome and then conquer it.

The Royal Road was an ancient highway rebuilt by Darius the Great in the 5th century BC, it permitted mounted couriers to travel 1677 miles, from Susas to Sardis, in nine days and so it established communication throughout the Persian Empire. Herodotus, an ancient greek historian, wrote that "There is nothing faster in this world than these Persian couriers".

The Royal Road was an ancient highway rebuilt by Darius the Great in the 5th century BC, it permitted mounted couriers to travel 1677 miles, from Susas to Sardis, in nine days and so it established communication throughout the Persian Empire. Herodotus, an ancient greek historian, wrote that "There is nothing faster in this world than these Persian couriers".

you didn't list the options. however, a few communist countries today are: the people's republic of china, north korea, and cuba.