This would be called a trade-of B.
The reason why this is correct is because if you can only build one thing as a company and you decide that building war equipment is more important to you, then you're doing a trade-off between building butter-making machines and army tanks.
Answer:
Once when preparing for a Spanish test I used repetition to help me study. This technique was useful for me, because when I wrote out vocabulary words and continued to review them until the day of the test it helped me remember the words a lot easier.
Answer:
it is c. and d because of me
