Final answer:
Mark wanted Helen and the kids to leave him behind in 'Alas, Babylon' because he thought it was safer for them to seek refuge elsewhere, which is a manifestation of his protective instincts. Option d) Mark thought it was safer for Helen and the kids to leave and seek refuge elsewhere is the correct answer.
Step-by-step explanation:
The question pertains to the character motivations in the novel "Alas, Babylon." Specifically, it asks why Mark wanted Helen and the kids to leave him behind. The answer is d) Mark thought it was safer for Helen and the kids to leave and seek refuge elsewhere.
This reflects a common theme in literature where a character may feel that separating from loved ones is a necessary sacrifice for their safety, a situation seen in various contexts from Roman law practices regarding citizenship and marriage to the strategies of refugees seeking freedom or the survival decisions in post-apocalyptic scenarios.