Step 1: Analyzing the Block Sequence.
The blocks are stacked in a particular pattern, with each subsequent block rotated in a specific way. When the sixth block is added, it should continue the pattern established by the other blocks.
Step 2: Identifying the Correct Top View.
By observing the sequence, option (c) C shows the correct top view when the sixth block is added to the sequence.
Step 3: Conclusion.
Thus, the correct top view is option (c) C.
\[
\boxed{\text{The correct answer is (c) C.}}
\]