premise: How to choose the healthiest salad greens<br>Look for low-calorie greens. If your idea of healthy is synonymous with low in calories, you might choose red leaf lettuce. This lettuce, like all varieties of lettuce, is mostly water.
hypothesis: All lettuce is not red.
reason: The text says to choose red leaf lettuce, meaning that there are definitely different colors of lettuce available. The system doesn't understand the implication.