Introduction:
The phylum Arthropoda is one of the largest phyla in the animal kingdom, encompassing a diverse group of organisms including insects, spiders, crustaceans, and millipedes. One of the distinguishing features of arthropods is their nervous system, which includes a nerve cord that runs along the ventral side of the body.

Nerve cord in arthropods:
The nerve cord in arthropods is a longitudinal structure that serves as the main pathway for transmitting nerve signals throughout the body. It is composed of a series of ganglia, which are clusters of nerve cell bodies, connected by a pair of nerve fibers called commissures. The nerve cord is responsible for coordinating movement, sensory perception, and other essential functions in arthropods.

Nerve cord characteristics:
To determine the characteristics of the nerve cord in arthropods, we need to consider its structure, composition, and arrangement within the body. Based on these factors, we can evaluate the given options:

1. Single, hollow, ganglionated:
- The nerve cord is a single structure, meaning it runs as a single unit along the ventral side of the body.
- It is hollow, allowing for the passage of nerve signals.
- The nerve cord is ganglionated, meaning it contains ganglia or clusters of nerve cell bodies.
- This option accurately describes the characteristics of the nerve cord in arthropods.

2. Single, solid, ganglionated:
- The nerve cord is not solid but rather hollow, as mentioned in the previous option.
- Therefore, this option does not accurately describe the characteristics of the nerve cord in arthropods.

3. Double, solid, ganglionated:
- The nerve cord in arthropods is not double but rather a single structure.
- This option does not accurately describe the characteristics of the nerve cord in arthropods.

4. Double, hollow, non-ganglionated:
- The nerve cord in arthropods is not double but rather a single structure.
- Additionally, it is ganglionated, containing clusters of nerve cell bodies.
- This option does not accurately describe the characteristics of the nerve cord in arthropods.

Conclusion:
Based on the characteristics of the nerve cord in arthropods, the correct option is (a) single, hollow, ganglionated. This accurately describes the structure, composition, and arrangement of the nerve cord in animals from the phylum Arthropoda.