In one multiple choise question, there was the sentence "Ich danke dem Verbraucher" where I replied by "I thank the consumer". Nevertheless my answer was considered as wrong, since there was supposedly another correct answer which I missed, saying "I thank the consumers". Shouldn't it then be "den Verbraucher" in German?
Dativ plural gets -n all around. Article, adjective, noun. In the case of Verbraucher: dem Verbraucher , den Verbrauchern. Many people tend to forget that extra -n after nouns. But you are right on the principle. The other answe was wrong. Report it with feedback. They do patch up mistakes.