Social & Preventive Medicine Bladder cancer can occur in those who are working in chimney for 25 years. Which is the best study for this relationship ? A Meta-analysis B Cross-sectional study C Randomized control trial with double blinding D Coho study 💡 Explanation Bladder cancer can occur in those who are working in chimney for 25 years. Which is the best study for this relationship ? ✓ Correct Answer: A. Meta-analysis