The correct option is A Crop
Crop is the largest part in alimentary canal of cockroach.
In cockroach, the mouth opens into a short tubular pharynx, leading to a narrow tubular passage called oesophagus. This in turn opens into a sac like structure called crop used for storing of food. The crop is followed by gizzard. Gizzard helps in grinding the food particles. In the hindgut, the food passes through ileum, colon and rectum. The rectum opens out through anus.