Companion cells are specialized cells found in the phloem tissue of plants. They are closely associated with sieve tube elements, which are responsible for the transport of sugars and other organic compounds in plants. In the given options, gymnosperms, bryophyta, and pteridophyta are all types of plants that do not have true companion cells. True companion cells are unique to angiosperms, which are flowering plants. This means that the correct option is 4, Angiosperms. Alert - However, it is important to note that while angiosperms have true companion cells, gymnosperms do have some cell types that perform similar functions, but they are not considered true companion cells.