What are the nomenclatures for WP rounds?

The correct nomenclatures for WP (White Phosphorus) rounds are M110 and M1121. WP rounds are primarily used for their smoke-making capabilities, obscuring movements or targeting, as well as for incendiary effects. The M110 is a standard artillery projectile filled with white phosphorus, while the M1121 is a variant designed for similar roles, often used in conjunction with different artillery systems including howitzers.

The other options consist of nomenclatures that refer to different types of munitions not primarily recognized for their unique WP characteristics. For example, while M805 and M487 may refer to other artillery rounds, they do not pertain to WP munitions. Similarly, M303 and M550, as well as M911 and M203, are either different munitions or systems unrelated to white phosphorus capabilities. Understanding the specific designations helps in grasping the use and function of various artillery rounds accurately.