In this question, it's asking what immigrants the quota system favored.
Your answer would be D). Europe
The quota system was placed in order to restrict the amount of immigrants a country can send.
During this time, the quota for Europe was very high, which resulted in a lot of immigrants coming from European countries.
However, other countries had a disadvantage with the quota system. For example, places like Japan and China were really affected by this, due to the fact that their quotas were very low, so they could only send a few immigrants.
Your other answer choices A, B, and C were not favored by the quota system, since they were the regions that had low quotas.
This leads to the answer choice D). Europe as your correct answer.