In the context of minimum necessary income for sponsorship, what does the term "minimum necessary income" refer to? Question 7 options: a) The before-tax annual income necessary to support the sponsor, their family members, the sponsored foreign national, and every other person covered by a still-effective undertaking. b) The average income for urban areas of residence with 500,000 persons or more. c) The income threshold set by the sponsor's spouse or common-law partner for co-signing an undertaking. d) The annual income required to support only the sponsored foreign national and their family members