A desire to protect American cities in the event of a Soviet invasion was most attributable is the expansion of the interstate highway system in the 1950s.
The Interstate Highway System is a network of controlled-access roadways in the United States that is part of the National Highway System. The system has routes in Hawaii, Alaska, and Puerto Rico, and it runs across the contiguous United States.
Thus, option B, A desire to protect American cities in the event of a Soviet invasion is correct.
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