The answer is true because depending on the assignment it doesn't have to be extensive
Peggy thinks negative and tends to see the worst aspect of things.
You didn't give the options. However, i'll try.
To me, a stone cannot be ethical because it cannot suffer. Indeed, the capacity for suffering must be satisfied before we talk about interest in a meaningful way. For instance, nothing we could possibly do for a stone could make a difference in its welfare. It don't have interest. Whereas, we, humans have interest. Therefore we can be ethical because we are sentient beings that can be benifited or harmed. It's because we can experience pain as a result.
Hope this helps !
Photon
Explanation: The rule for indefinite article usage is as follows: Use before nouns (or adjectives) that start with a consonant sound. Use before nouns (or adjectives) that start with a vowel sound.