C

Risk of complications:
• Control (old drug) = 1 800 / 15 225 ≈ 11.8%  
• Intervention (new drug) = 1 620 / 15 225 ≈ 10.6%  

Absolute Risk Reduction = 11.8 % – 10.6 % ≈ 1 %.  
Relative Risk = 10.6 % / 11.8 % ≈ 0.9.  

Thus ARR ≈ 1 % and RR ≈ 0.9, matching option C [Jaeschke et al., 1995, PMID 7828099].