In Spanish, 'Hola' is not a formal way to greet señora López compared to 'Buenas tardes', 'Buenas noches', or 'Buenos días'.
C. Hola is NOT a way to greet señora López. In Spanish, 'Hola' is a general greeting that can be used in informal settings. For a more formal greeting such as addressing Señora López, 'Buenas tardes', 'Buenas noches', or 'Buenos días' would be appropriate.