But does everyone on earth have an equal right to an equal
share of its resources? The spaceship metaphor can be
dangerous when used by misguided idealists to justify
suicidal policies for sharing our resources through
uncontrolled immigration and foreign aid. In their
enthusiastic but unrealistic generosity, they confuse the
ethics of a spaceship with those of a lifeboat.
---Garrett Hardin, "Lifeboat Ethics: The Case Against
Helping the Poor
Which word does the author use to show that he thinks the spaceship
metaphor is a bad one?

A. unrealistic

B. ethics

C. generosity

D. enthusiastic