An example of a caryopsis is

A caryopsis is a type of fruit that is commonly found in grasses and grains. It is a one-seeded fruit where the seed coat is fused to the fruit wall. This means that when the fruit is mature, the seed is tightly attached to the fruit wall and cannot be easily separated from it. An example of a caryopsis is a maize grain. When you look at a maize grain, you can see that the outer layer (the pericarp) is fused to the seed coat, making it a caryopsis. The other options, guava, coconut, and tomato, are not examples of caryopsis.