Read the following statements:

(i) A vestigial organ called the "vermiform appendix" arises from the caecum.

(ii) Serosa is the innermost layer in the wall of the alimentary canal and is made up of thin mesothelium.

(iii) Muscularis is formed by smooth muscles and is arranged into outer circular and inner longitudinal layers.

(iv) The opening of the stomach into the duodenum is guarded by the pyloric sphincter.

Which of the above statements are correct?