One of the secondary aims of the PreEMPt study was to assess the safety of the prehabilitation exercise programme. A serious adverse event was defined as any adverse event or adverse reaction that results in death, is life‐threatening, required hospitalisation or prolongation of existing hospitalisation, results in persistent or significant disability or incapacity.

There were no serious adverse events observed in the 23 participants during the prehabilitation exercise programme. Calculate a 95% confidence interval for the serious adverse event rate in the PreEMPt study.

The 95% confidence interval for the serious adverse event rate is:

A. −14.3 to 14.3%

B. 0.0 to 14.3%

C. 0.5 to 14.0%

D. 1.0 to 12.5%

E. 1.5 to 12.5%