The sample size calculation for the trial was based on detecting a 15% absolute difference in the proportion of patients who experience a recurrence of a haemorrhoid at 12 months between the RBL and HAL treated groups (i.e. 30% rate in the control treated RBL patients versus a 15% rate in HAL treated patients). Express this difference as an odds ratio effect for recurrence of a haemorrhoid at 12 months between the HAL and RBL groups.

A. 0.26 B. 0.41 C. 0.85 D. 2.43 E. 3.86