Explanation:

- Option 1: "People have still believed in superstitions." This suggests that people may have started and stopped believing multiple times, which is not the intended meaning.

- Option 2: "People are still believing in superstitions." This ongoing action focuses on the present, but it is less common in general usage.

- Option 3: "People still believe in superstitions." This is clear, simple, and accurately describes a timeless or ongoing situation. It's the best choice.

- Option 4: "People still believed in superstitions." This past tense suggests that the belief continued in the past, but lacks ongoing relevance.