The correct option is
E Intrinsic factor
The parietal cells are located in the middle part of the glands of the fundus-body region of the stomach. They secrete gastric acid, i.e. hydrochloric acid (approximately 0.16 M, pH ≥ 0.8) and secrete the intrinsic factor, which is a vitamin B12-binding protein.
Hence, the correct answer is (D)