Answer:
1) Greece
2) Switzerland
3) 5 barrels of oil
3) 1/10 crates of olive
4) B. 12 barrels of oil per crate.
Explanation:
A) Greece forgoes a lesser amount of oil barrels to make the same amount of olive as Switzerland, so it has a comparative advantage in making olive.
B) Switzerland will save more oil if it doesn't produce olives than Greece would save, so it has a comparative advantage in producing barrels of oil.
C) since Greece produces one crate of olive with 5 barrels of oil, it will only gain in any trade trading more than 5 barrels of oil for every crates of olive.
D) since Switzerland produces 1 crate of olive with 10 barrels of oil, it will only gain in a trade trading 1/10 crates of olive for one barrel of oil.
E) only option B will satisfy both countries.