Which words in this sentence are an independent clause?


An American businessperson discovered a stockpile of King Tut's items that had been hidden in a safe tomb, which had a clay sealing covering it.


A.

that had been hidden in a safe tomb, which had a clay sealing


B.

An American business person discovered a stockpile of King Tut's items


C.

which had a clay sealing covering it


D.

that had been hidden in a safe tomb