how do we say, \goodbye\ in a bit more formal way?\nchao\nadiós\nya me voy\nhasta mañana

how do we say, \goodbye\ in a bit more formal way?\nchao\nadiós\nya me voy\nhasta mañana
Answer
Brief Explanations:
"Chao" is an informal Chinese - influenced way to say goodbye. "Ya me voy" means "I'm leaving" in Spanish and is informal. "Hasta mañana" means "see you tomorrow" and is not a general formal goodbye. "Adiós" is a more formal way to say goodbye in Spanish.
Answer:
B. adiós