That was the time when there was a hunger for foreign knowledge and foreign thought

The correct answer is appetite.

An appetite is a strong desire or craving for something. In this case, the people of the time had a strong desire for foreign knowledge and foreign thought. They were eager to learn about other cultures and ways of thinking.

The other options are not as accurate. A wish is a hope or desire for something to happen. An undesired thing is something that is not wanted. Generosity is the quality of being kind and giving.

In conclusion, the correct answer is appetite.