What kind of tree remains green throughout the year and does not lose its leaves?

The correct choice identifies an evergreen tree, which is characterized by its ability to remain green and retain its leaves throughout the entire year. This adaptation allows evergreens to photosynthesize and take advantage of sunlight during different seasons, especially in regions with varying climates.

Evergreen trees include conifers such as pines, spruces, and firs, as well as some broadleaf species that do not shed their leaves seasonally. This trait is advantageous for maintaining foliage density and providing year-round shelter and food for wildlife, as they do not go through the dormant period that deciduous trees experience, where they lose leaves in the fall.

In contrast, deciduous trees shed their leaves in autumn as part of their seasonal cycle, which prepares them for winter conditions and helps conserve resources. Shade trees, while they can be either deciduous or evergreen, typically refer to trees providing shade due to their mature canopy. Tropical trees can be either evergreen or deciduous depending on their specific species and environmental conditions, but the term does not specifically define a tree's leaf retention behavior. Thus, evergreen trees are distinct in their perennial foliage, making the identification of B as the correct answer accurate.