I think it was D. Basically the US sent South Vietnam troops because they feared Vietnam would become communist, which would spread to the rest of Asia. The US sent supply and materials to South Vietnam to help the spread. I don't know if the answer that best suits that is D, but that's what I would say.
Continued into the 2010s duhhh
The goal of Steve Jobs' speech is to persuade the graduates to find the jobs that they can truly love because of their passion for the definite activities.
Electricity=Thomas A. Edison
Telephone=Alexander Graham Bell
Telegraph= Samuel F. Morse
Oil=Edwin L. Drake
Steel= Bessemer process
Hopefully this was helpful!