Elle quiere entender cuánto, en promedio, le cuestan sus anuncios por clic. ¿Qué estadística le ayudaría a entender esto?

The correct answer is aCPC (average Cost Per Click). This metric directly measures the average amount Elle pays for each click on her ads, providing a clear understanding of her ad cost per interaction. "Inversión" (Investment) is too broad; it represents the total amount spent, not the cost per click. "Impresiones" (Impressions) refers to how many times her ad was shown, not how much she paid per click. "CPC" (Cost Per Click) is a general term that can refer to a bid or a specific instance of a click cost, but "aCPC" specifically denotes the average cost, which is what Elle wants to understand over a period.