The options listed are not related to the question. and if they were related in any sense then I would say the cheapest thing on the list is a phone card so I guess you can buy that and save the most for your travel as you can use phone cards anywhere as they have 1800 numbers which are free from any public phone.
Change the line in word, it basically returns
Materials
materials are the only physical thing
Answer:
I'm very sorry if I'm wrong but I think it's A
Answer:
Because it helps you prove that you're you to third parties who wouldn't know otherwise. A CA helps you to establish trust with others because they're trusted for issuing valid, reliable certificates — and that trust is integral to public key infrastructure (PKI).
Explanation:
with this info I believe it is a A and C