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