Final answer:
The Staghorn fern (Platycerium) is the type of eusporangiate fern that hangs from trees. Whisk ferns like Tmerpterous, while also eusporangiate ferns, do not typically hang from trees. The correct option is b.
Step-by-step explanation:
The type of eusporangiate fern that hangs from trees is the Staghorn fern (Platycerium). Whisk ferns, such as the genus Tmerpterous, have green branching stems with spherical yellow sporangia but do not typically hang from trees.
Instead, whisk ferns lack leaves and roots, features they lost through evolutionary reduction. They conduct photosynthesis through their green stems, with sporangia located at the tips or branch nodes.
The Bird's nest fern (Asplenium nidus) and the Elkhorn fern (Platycerium bifurcatum) are also eusporangiate ferns that may grow on trees, but the specific eusporangiate fern known for hanging from trees as mentioned in the question is indeed the Staghorn fern. The correct option is b.