That's correct! The correct answer is "b. está". In Spanish, when describing the condition or state of something, we typically use the verb "estar" which means "to be" in English. In this case, we are talking about the current state of cleanliness of Alfredo's bedroom, so the correct form of "estar" is "está" to match the third person singular subject "tu dormitorio" ("your bedroom"). Therefore, the correct translation of the phrase "No _____ muy limpio hoy" is "Not está very clean today."
