Ventilators are installed near the ceiling of the room, because

Ventilators are installed near the ceiling of the room primarily because the exhaled hot air rises up and goes out; option [A]. Hot air is less dense than cold air, causing it to ascend towards the ceiling. By placing ventilators near the ceiling, they effectively expel this hot air, promoting better air circulation and ventilation within the room.
Additionally, installing ventilators near the ceiling helps to provide cross ventilation in the room. Cross ventilation involves the flow of air through opposing openings, such as windows or ventilators, allowing fresh air to enter while stale air exits. Placing ventilators strategically near the ceiling enables them to work in conjunction with other openings in the room, facilitating the exchange of air and maintaining indoor air quality.

Moreover, ventilators near the ceiling do not necessarily provide light to the room. Their primary function is ventilation, not illumination. Lighting fixtures or windows are typically used to provide illumination in a room, while ventilators focus on improving air quality and comfort.

As for aesthetics, the placement of ventilators near the ceiling is more practical than decorative. While aesthetics may play a role in design considerations, the primary reason for installing ventilators near the ceiling is to optimize air circulation and ventilation within the room.