The underlined portion modifies auto immune disease. It describes auto-immune disease as a disorder.
Also, the intended meaning of the sentence is about most scientists agreeing on the point that the disorder/disease is caused by our immune system’s response to the invading pathogen.
A. a disorder most scientists agree that is caused by response to the invading pathogen by our immune system.
Incorrect. whose response?. Also, that is caused by ...... by ...... is confusing.
B. a disorder most scientists agree to be caused by our immune system
in responding to the invading pathogen.
'responding to' implies - response to something that is still happening at the time of action.
whereas we need 'in response to or response' implying 'response to something that is already done'.
C. which most scientists
agree on as a disorder caused by our immune system which responds to invading pathogens.
meaning change- firstly, on what point the scientists agree and secondly, what caused the disease. Incorrect
D. which most scientists agree to be disorder caused by invading pathogens being responded to by our immune system
Apart from other errors already discussed, the usage of being as modifier is incorrect.
E. a disorder that most scientists agree is caused by our immune system’s response to the invading pathogen. Correct in all respects.
Answer E