Given the question: Read the following article and select the best answer. Article: It's a popular belief that a fish's memory lasts for only seven seconds. It may seem sad to think that they don't remember what they've eaten or where they've been, and they don't recognize you or any of their friends -- every moment in their life would be like seeing the world for the first time. But don't be so quick to feel sorry for them. A new study has found that fish have a much better memory than we used to think. In fact, certain species of fish can even remember events from as long as 12 days ago. In the study, researchers from MacEwan University in Canada trained a kind of fish called African cichlids to go to a certain area of their tank to get food. They then waited for 12 days before putting them back in the tank again. Researchers used computer software to monitor the fish's movements. They found that after such a long break the fish still went to the same place where they first got food. This suggested that they could remember their past experiences. In fact, scientists had been thinking for a long time that African cichlids might have a good memory. An earlier study showed that they behaved aggressively in front of certain fish, perhaps because they remembered their past "fights". But until the latest findings, there was no clear evidence. Just as a good memory can make our lives easier, it also plays an important part when a fish is trying to survive in the wild. "If fish are able to remember that a certain area contains safe food, they will be able to go back to that area without putting their lives at risks," lead researcher Trevor Hamilton toldLive Science. For a long time, fish were placed far below chimpanzees, dolphins and mice on the list of smart animals. But this study has given scientists a new understanding of their intelligence. Question: According to the article, people used to believe that _ . - fish could only remember part of their past experiences - fish could remember things that happened 12 days ago - a fish's memory lasted for only seven minutes - fish didn't recognize any of their friends
The answer is:
fish didn't recognize any of their friends