The correct option is C Water
Areca catechu is a coastal plant and possesses fibrous mesocarp and stony endocarp.
Dispersal by wind requires seeds or fruits which are lightweight and which possess morphological structures as hairs, wings, etc. Fibrous mesocarp and stony endocarp does not help in dispersal by wind.
Dispersal by animals requires certain structural peculiarities on seed or fruit surface. Such structural peculiarities are hooks, spikes, sticky glands. Fibrous mesocarp and stony endocarp does not help in dispersal by animals.
In mechanical means of seed or fruit dispersal the rapid plant movement occurs after ripening and seeds or fruits are thrown away from parent plant. Fibrous mesocarp and stony endocarp does not help in dispersal by mechanical means.
Areca catechu is a coastal plant and possesses fibrous mesocarp enables floating and stony endocarp protects from external injury. Such fibrous fruits can float for long distances.
Therefore, the correct answer is option C.