Which type of smoke is placed on or near the threat to suppress threat observers and to minimize their vision?

Obscuring smoke is specifically designed to limit visibility for enemy forces, effectively suppressing their ability to observe and engage. The primary purpose of this type of smoke is to create a veil that hinders the line of sight, thereby minimizing the threat from observers. It is used strategically to conceal movements or positions from hostile observation, which is crucial in combat scenarios where maintaining stealth is important.

Deception smoke, while also used to confuse the enemy, doesn't have the same primary focus on obstructing vision as obscuring smoke does. Screening smoke is generally employed to protect friendly troops from observation by providing a smokescreen that aids in movement and repositioning, rather than directly suppressing observer capabilities. Masking smoke serves similar purposes by obscuring one's own forces but does not necessarily mean it is placed right on or near the threat to specifically limit their vision.

Therefore, obscuring smoke is the right choice as it directly addresses the need to suppress threat observers by minimizing their ability to see and observe effectively.