The remark SLP161 in a METAR report signifies which of the following?

The remark SLP161 in a METAR report denotes sea level pressure in hectopascals (hPa). The "SLP" stands for "Sea Level Pressure," and the number that follows represents the pressure value but is given in a specific format. In this case, the value of 161 refers to 1016.1 hPa when interpreted correctly. This is based on the convention that the SLP value is reported by taking the last three digits and adding "10" in front of it, which fits the standard practice for reporting sea level pressure in meteorological contexts.

Meteorological data often use hectopascals as the primary unit for pressure, which is more straightforward for reading from the report. Therefore, understanding SLP as referring to sea level pressure measured in hectopascals is essential for interpreting various weather data accurately.

The other options are not applicable here, as sea level pressure is specifically denoted by hectopascals in METAR reporting, and the alternative units such as inches, millibars, or temperatures in Celsius, do not relate to the SLP remark as framed in this question.