Why, According to Gill, Does Leon Kass Think the Notion

Why, according to Gill, does Leon Kass think the notion of being "better off dead" is incoherent?

A) because dead people no longer exist, and thus cannot benefit from choosing to die.
B) because some things (e.g., long-term torture) are worse than death.
C) because there has yet to be a satisfactory philosophical explanation of why death is bad.
D) because death is, by definition, undesirable.