Hello there!
They already gave you the answer just by saying "while serving his or her nation". So, the only way you can serve your nation is when you join the military.
So, the correct missing word is Joining the military.
I hope this helps!
Numeric Keypad is the answer
Answer:
This is the second question like this I've seen. They aren't the greatest.
Explanation:
The question is not good. The answer would be option a, Transport even though it doesn't make a whole lot of sense when you really go into detail.
It could also be option d, Application but I think they're going for the first.
