Among Bryophytes, Only the Sporophytes of Mosses and Hornworts Have

Among bryophytes, only the sporophytes of mosses and hornworts have stomata, whereas stomata are missing from liverwort sporophytes. If the common ancestor of all bryophytes had sporophytes that bore stomata, then which of these might account for their absence from liverwort sporophytes? If, in contrast to early mosses and hornworts, early liverwort sporophytes had

A) more-effective transport of glucose from gametophyte to sporophyte.
B) increased robustness (i.e., thicker, more massive tissues) .
C) increased nutritional independence from the gametophyte.
D) decreased need to broadcast spores long distances.