Detailed Instructions: In this task, you will be given sentences in which your task is to recognize the name of the organ of the body. An organ is a collection of tissues that structurally form a functional unit specialized to perform a particular function. Although there might be several correct answers, you need to write one of them.
Q:  An abnormal high velocity arterial blood flow signal observed within masses in the GB or in the GB wall is a significant feature of primary GB cancer and thus helps to differentiate primary GB cancer from metastatic and benign lesions of the GB .
A:
GB