A succulent is any plant that stores water in its leaves, stems, or roots. They come in all shapes and varieties, and some even produce flowers. Some of the best-known succulents are the aloe and agave plants. Cactuses are also a type of succulent. They are beautiful to look at and do not take much work. In fact, you only need to water succulents once a month in the winter. In the hot season, just give them water once a week. Your plants will reward you by growing slowly and steadily for many years to come.

Which topic sentence fits best with the details above?
A. Other green houseplants have to be watered frequently and require more care.
B. Some of the succulents in the Arizona desert grow to be 6 or 8 feet tall.
C. A cactus only needs a little bit of water, but it will die if you give it too much.
D. Succulents are popular houseplants that look pretty and are easy to care for.