Why have biologists hypothesized that the first land plants had a low

The question is incomplete as it does not have the options which are:

Why have biologists hypothesized that the first land plants had a low, sprawling growth habit?

A) They were tied to the water for reproduction and thus needed to remain in close contact with the moist soil.

B) The ancestors of land plants, green algae, lack the structural support to stand erect in air.

C) Land animals of that period were small and could not pollinate tall plants.

D) There was less competition for space so they simply spread out flat.

Option-B

Explanation:

The first land plants which evolved from the aquatic plants were the green liverworts and mosses which evolved around 470 million years ago.

The first land plants belong to bryophytes which evolved from the green algae especially the Chara and Chara like algae.

These green algae although were long but they lacked the structural modification and compounds which could help them stand erect.

When these plants evolved they turned themselves on the mosses which can grow on the seashore. Due to this, these plants had a sprawling growth habit.

Thus, Option-B is the correct answer.