Which one of the following provides buoyancy to aquatic plants to help

Which one of the following provides buoyancy to aquatic plants to help them float?

Aerenchyma
Tracheid
Guard cell
Sclerenchyma
This question was previously asked in
UPSC Geoscientist – 2020
Aerenchyma provides buoyancy to aquatic plants.
Aerenchyma is a modified parenchyma tissue found in many aquatic and wetland plants. It contains large air spaces (lacunae) that provide buoyancy, allowing the plant to float on the water surface. These air spaces also facilitate gas exchange (oxygen and carbon dioxide) to submerged tissues.
Tracheids are components of xylem involved in water transport and support. Guard cells surround stomata and regulate gas exchange but are not involved in buoyancy. Sclerenchyma provides mechanical support and strength due to its thick, lignified cell walls. Only aerenchyma is specifically adapted for providing buoyancy through its air-filled cavities.