Final answer:
Male sea spiders carry developing eggs on their ovigers, which are specialized appendages located between the chelicerae and pedipalps in the subphylum Chelicerata.
So, the correct answer is B.
Step-by-step explanation:
Male sea spiders have a subsidiary pair of legs called ovigers, which they use primarily for carrying developing eggs. These ovigers are located between the chelicerae and pedipalps of the Chelicerata subphylum. Within this subphylum, chelicerae, which serve as specialized mouthparts, are the first set of appendages and are different in function compared to mandibles found in other arthropods.
Chelicerates do not have antennae; instead, some of their sensing functions are delegated to pedipalps, which also aid in feeding. The Chelicerata subphylum includes diverse species such as spiders and scorpions, and these creatures have evolved various reproductive strategies, including both external and internal fertilization depending on the species.
So, the correct answer is B.