Concept:
Each listed software has a specific purpose, and the question asks for the one used to directly download and process survey observations recorded by a total station.
Step 1:
Review the roles of the options: STAAD Pro is a structural analysis and design package, Primavera is a project planning and scheduling tool, and Autodesk Revit is a building information modelling (BIM) software. None of these handles raw total station survey data.
Step 2:
Surfer is a surface mapping and contouring program that accepts coordinate and elevation data, including data downloaded directly from a total station, and is commonly used to process and visualise survey data after fieldwork.
Answer: Option (2) — Surfer.