In the US if you walk into any major grocery store and ask for coriander you'll be directed to the spice aisle, not the fresh produce section. Here the leaf stage of coriander is called cilantro, and only the seeds are called coriander. I realize there may be differences in other countries which is why I made the quiz specifically about culinary herbs in the US. (For example, I read that in India it is called hara dhania, but that isn't accepted either.) Since coriander is used in the clue it should be obvious that it wouldn't also be the answer.