Final answer:
At the beginning of the 20th century, the two independent African nations were Ethiopia and Liberia, with Ethiopia being the correct answer to the student's question.
Step-by-step explanation:
The two African nations that were independent at the beginning of the 20th century were Ethiopia and Liberia. Ethiopia, formerly known as the Kingdom of Ethiopia, successfully resisted European colonization efforts during the partitioning of Africa by European powers. Liberia, on the other hand, was established as a homeland for freed slaves and also maintained its independence during this period. Therefore, the correct answer to the question is Ethiopia.