Step 1: End correction.
Resonance tube: anti-node forms slightly outside open end: \( L_{eff} = L + e \), \( e \approx 0.6r \).
Step 2: Other experiments.
Pendulum, meter bridge, optical bench - no analogous large systematic correction term.
Step 3: Final.
\[ \boxed{\text{Resonance tube - highest correction index}} \]