to give an affirmative tú command,

a) use a conjugation that looks the same as the regular past-tense form we use for él, ella, and usted.
b) use a conjugation that looks the same as the regular present-tense form we use for usted only.
c) use a conjugation that looks the same as the regular past-tense form we use for usted only.
d) use a conjugation that looks the same as the regular present-tense form we use for él, ella, and usted.