Independent gametophyte and sporophyte are found in:

Explanation

The correct answer is Ectocarpus. In Ectocarpus, both the gametophyte and sporophyte stages are independent of each other, which is characteristic of its alternation of generations. This is unlike most non-vascular plants like Polytrichum (mosses) and Liverworts, where the sporophyte is dependent on the gametophyte. Selaginella, although having a complex life cycle with heterospory, does not have fully independent gametophytes.