The question asks for the most suitable air pollution control device for removing very fine particulates, such as cement dust, from hot exhaust gases originating from a cement kiln. Let's examine each option:

1. Baghouse: Baghouse filters are effective in capturing dust particles, including fine ones. However, they may not always be the most efficient at high temperatures, unlike the electrostatic precipitator, which is specifically suited for such conditions.
2. Cyclones: Cyclone separators are generally used for large particles because they rely on centrifugal force to remove particulates. They are less efficient for removing fine particles like those found in cement dust.
3. Venturi scrubber: While Venturi scrubbers can capture fine dust particles, they require liquid and are generally less efficient for dry particulates compared to electrostatic precipitators.
4. Electrostatic precipitator (ESP): ESPs are particularly effective for fine particle removal in industrial exhaust gases. They work by charging the particles electrically and attracting them to collector plates. This method is very efficient for fine particulates at high temperatures without requiring liquids.

Considering the properties and operational conditions, the Electrostatic Precipitator is the most appropriate device for removing very fine particulates like cement dust from hot exhaust gases. Such devices are particularly effective for high-temperature environments typically found in cement kilns.

In conclusion, the correct answer is: Electrostatic precipitator.