Condensation nuclei may be:

Particles of dust
Nitric acid particles
Smoke from forest fires
Salt from the ocean E. All of these

The correct answer is: E. All of these

Condensation nuclei are tiny particles around which water vapor can condense to form clouds. They can be of biological origin, such as bacteria or pollen, or they can be of inorganic origin, such as dust, salt, or soot.

Particles of dust are the most common type of condensation nuclei. They are found in the air everywhere, and they can come from a variety of sources, such as soil, rocks, and plants. Dust particles are very small, typically less than 1 micrometer in diameter. This makes them ideal for condensing water vapor, because they have a large surface area relative to their volume.

Nitric acid particles are another type of condensation nuclei. They are formed when nitric oxide, a gas produced by combustion, reacts with water vapor in the atmosphere. Nitric acid particles are very small, typically less than 0.1 micrometer in diameter. They are also very hygroscopic, which means that they attract water vapor from the air. This makes them very effective at condensing water vapor.

Smoke from forest fires is a type of condensation nuclei. It is formed when wood and other organic materials are burned. Smoke particles are typically very small, less than 0.1 micrometer in diameter. They are also very hygroscopic, which means that they attract water vapor from the air. This makes them very effective at condensing water vapor.

Salt from the ocean is a type of condensation nuclei. It is formed when seawater evaporates. Salt particles are typically very small, less than 0.1 micrometer in diameter. They are also very hygroscopic, which means that they attract water vapor from the air. This makes them very effective at condensing water vapor.

In conclusion, all of the options listed in the question can be condensation nuclei.