Explanation:

- Here’s the thing: when you’re talking about a “unique responsibility,” you’re referring to one specific, important kind of responsibility.

- Option 1: “some” – This is vague and plural. You’d use it for “some responsibilities,” meaning more than one, not for a singular “unique responsibility.” Doesn’t fit.

- Option 2: “a” – This is spot on. You say “a unique responsibility” because you’re talking about ONE clear, individual responsibility. It’s the right article when the word starts with a consonant sound, and “unique” does.

- Option 3: “an” – Sounds close, but no. “An” is for words that start with a vowel sound. “Unique” actually starts with a “yu” sound, so “an unique responsibility” would just sound off.

- Option 4: “few” – Way off here. “Few” means a small number, again plural. Would only work for “few responsibilities,” which isn’t what we want.

- Bottom line: “a unique responsibility” is the natural, correct way to say it in English.