In the Great Australian Desert, Rainfall Averages About 30 Centimetres

In the Great Australian Desert, rainfall averages about 30 centimetres per year. Yet, it is not uncommon when hiking in this extremely arid zone to encounter mosses and ferns. One such plant is called "flower of stone". It is not a flowering plant, nor does it produce seeds. Under arid conditions, its leaflike structures curl up. However, when it rains, it unfurls its leaves, which form a bright green rosette on the desert floor. Consequently, it is sometimes called the "resurrection plant". At first glance, it could be a fern, a true moss, or a spike moss.
-Which of the following features is most important for true mosses and ferns to reproduce in the desert?

A) that the sporophytes occupy only permanently shady, north-facing habitats
B) that the sporophytes hug the ground, growing no taller than six centimetres
C) either that their gametophytes grow close together, or that they be homosporous
D) that the sporophytes have highly lignified vascular tissues