What cleaning solution do we use to wash the helicopter?

The correct answer is MIL-PRF-85570 Type 2, a specific cleaning solution designed for use on military helicopters, including the MH-60S. This type of cleaning solution effectively removes dirt, grease, and other contaminants from the aircraft while being safe for both the materials of the helicopter and the environment. It adheres to military specifications that ensure its effectiveness and safety in aviation operations.

Using the correct cleaning solution is critical to maintaining the integrity and performance of the helicopter's surfaces and components. MIL-PRF-85570 Type 2, specifically, offers advantages in biodegradability, making it suitable for ground operations while minimizing environmental impact.

The other options are variations of the same specification but serve different purposes or have different formulations that might not be compatible with the specific cleaning needs of the MH-60S. Thus, MIL-PRF-85570 Type 2 is the best choice for washing the helicopter.