After months of voyage, Columbus arrived in ______ later proved to be a new continent.
正确答案： C
本题解析：
注意， 本句话并非定语从句， 而是宾语从句。 因为在介词 in 后面，应该用 what 引导的宾语从句， what 在宾语从句中作主语。
The professor asked a question, and David ________ a good answer.
He would have given you more help, if he ________ so busy.
It rained hard yesterday, ______ prevented me from going to the park.
It is important to ________ your skin from the harmful strong sunlight.
He was ______ to withdraw from running for the presidency.
The two girls competed with each other ______ the highest mark.
If the operation ________ carefully prepared, it would not have been successful.
The furniture in her bedroom is quite different from ________ in the living room.