Pneumatophores show

The correct option is negative geotropism (ageotropism).

To understand why this is correct, let us break down the concepts of plant tropisms and the function of pneumatophores:
Pneumatophores are specialized, aerial root structures found in plants growing in waterlogged, saline, or marshy soils (such as mangroves). Because the mud in these environments is devoid of oxygen, normal underground roots cannot perform aerobic respiration. To overcome this limitation, pneumatophores grow vertically upwards out of the water and mud into the air to take in oxygen.

Tropism refers to the growth or turning movement of a biological organism (typically a plant) in response to an environmental stimulus. Geotropism (or gravitropism) is a plant's growth response to the stimulus of gravity:
- Positive geotropism is growth in the direction of gravity (downwards, towards the center of the Earth), which is typical for standard roots.
- Negative geotropism (also referred to as ageotropism in this context) is growth against the force of gravity (upwards, away from the Earth's center).

Since pneumatophores grow upwards, opposite to the pull of gravity, they exhibit negative geotropism to facilitate gas exchange for the plant.