How is 2/8 of the sky covered by smoke at 2,500 feet AGL encoded in an observation?

The correct observation for 2/8 of the sky covered by smoke at 2,500 feet AGL is encoded as "FEW025." In aviation weather reporting, the term "FEW" indicates that there are a few clouds present, which is defined as coverage of 1 to 2 octas (or eighths) of the sky. Since 2/8 represents a coverage that falls within this range, "FEW025" is appropriate.

The other options provided are not suitable for describing this scenario. "SMK025" would likely indicate smoke at the altitude of 2,500 feet, but it does not convey any information about the coverage extent in terms of eighths. "OVC025" translates to overcast at 2,500 feet, which would imply complete cloud coverage (8/8), contradicting the presence of smoke as described. "SCB025" suggests scattered clouds, which also doesn't align with the specific smoke coverage mentioned. Thus, "FEW025" properly encapsulates the scenario where there is a limited but noticeable amount of smoke affecting visibility at that altitude.