Final answer:
The most likely scenario to involve hazardous material is the tractor trailer rig emitting a visible cloud, signifying a potential chemical spill or hazardous fumes.
Step-by-step explanation:
The situation that MOST likely involves a hazardous material is B) Tractor trailer rig emitting a visible cloud. This scenario suggests the potential release of a gas or vapor that could be dangerous, such as a chemical spill or hazardous fumes, which would require immediate attention and possibly the involvement of hazardous material cleanup procedures. In comparison, the other situations listed may involve risks, but they do not specify any obvious signs of hazardous materials being released.