Step 1 :Define the sets U, A, B, and C as given in the problem.
Step 2 :Find the union of sets A, B, and C. This includes all elements that are in A, B, or C.
Step 3 :Find the complement of the union of sets A, B, and C. This includes all elements in the universal set U that are not in the union of A, B, and C.
Step 4 :After calculating, we find that the union of sets A, B, and C includes all elements in the universal set U.
Step 5 :Therefore, the complement of the union of sets A, B, and C is an empty set, which means there are no elements in U that are not in the union of A, B, and C.
Step 6 :Final Answer: \((A \cup B \cup C)^{\prime}=\boxed{\varnothing}\)