Ambele variante sunt corecte, dar in functie de ce cuvant urmeaza, folosim fie a, fie an.
Exemple.
Daca avem dupa un cuvant care incepe cu o vocala, folosim "an".
He is an awesome guy.
I will have an orange.
Daca avem dupa un cuvant care incepe cu o consoana, folosim "a".
I will get a car soon.
I want to eat a grape.