What colors appear on the M8 paper if a chemical agent is present?

The presence of a chemical agent is indicated by the use of M8 paper, which detects nerve agents and blister agents. The correct answer, which states that red designates blister agents, yellow indicates 'G' nerve agents, and green shows 'V' nerve agents, accurately reflects the color coding system used with M8 paper.

When M8 paper comes into contact with chemical agents, it reacts in specific ways to show different colors depending on the type of agent. The red coloration indicates a blister agent such as mustard gas, which causes severe skin and respiratory issues. Yellow indicates a 'G' series nerve agent, which disrupts the nervous system and can be lethal. Green signifies a 'V' series nerve agent, which is even more toxic. This systematic color identification is essential for quick recognition and response in hazardous environments.

Focusing on the other options, they either misrepresent the colors associated with specific agents or do not encompass the full range of agents that M8 paper can detect. Therefore, choice B is the most accurate representation of how M8 paper functions in the context of chemical agent detection.