A 56yo woman is known case of pernicious anemia

A 56yo woman is known case of pernicious anemia. She refuses to take hydroxycobalamin IM as
she is needle shy. She asks for oral medication. Why will oral meds be not effective?

a. Intrinsic factor def
b. Malabsorption
c. Irritated gastric mucosa
d. Lack of gastric acidity

Ans. The key is A. Intrinsic factor def. [Vitamin B12 cannot be absorbed without intrinsic factor].

Can you explain the answer please?
I mean Pernicious anaemia is an autoimmune disease, in which 3 types of antibodies prevent the absorption of B12 (parietal canalicular antibodies, which bind to the mucosal parietal cells; blocking antibodies, which disrupt the binding of vitamin B12 to intrinsic factor; and intrinsic factor–B12 complex antibodies, which prevent the complex from binding to cubulin). So I thought the answer would be Malabsorption:(