Step 1: Understanding the question:
The question asks to identify the item that is NOT a technique for collecting data, among options that mix actual techniques with a methodological principle.
Step 2: Classify the options:
Interview, Observation and Survey are all concrete techniques sociologists use to gather primary data directly from respondents or settings.
Step 3: Identify the odd one out:
Objectivity, by contrast, is a methodological value/principle, the requirement that research be conducted without personal bias, not a technique for collecting data itself.
Final Answer:
Objectivity (option iii) is not a method of data collection.