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The correct answer is Elongated sporophyte
Explanation:
Hornworts, liverworts and mosses are the three types of bryophytes. Bryophytes are non-vascular plants lacing the xylem and phloem tissue. Hornworts are group of plants differ from mosses and liverworts in having elongated horn-like structure called sporophyte. The flattened, green plant body of a hornwort is the gametophyte as in mosses and liverworts. Examples of hornworts are Anthoceros, Notothylas.