This would not only keep Canadians involved in ballistic missile early warning, NORAD's ITWAA function, but would also involve them directly in strategic BMD interception operations.
While that represents a logical solution, it is the one option that Canadian negotiators are desperate to avoid because of their fear that, when Canadians are removed from the ITWAA role, Canada will be marginalized in North American security operations.
That is, Canada continues to participate in the ITWAA function of NORAD, which is directly linked to the BMD interception performed by NORTHCOM.
Politically, there is not much to distinguish options 2 and 3--that is, when BMD actually becomes operational, even as a test bed, Canadian NORAD personnel would in either case stay in their ITWAA chairs.
Canada would not be allowed to be in on US intelligence briefings that relate to the integration of the ITWAA and interception roles, and Canadians would be kept out of discussions related to BMD operational planning, interception scenarios, and the like.