Concept: Risk assessment is the process of identifying hazards, analysing vulnerability, studying exposure, and estimating possible losses.
Step 1: Understanding risk assessment.
Risk assessment helps to understand what can go wrong, who or what can be affected, and how severe the impact can be.
\[
\text{Risk Assessment} = \text{Hazard Assessment + Vulnerability Assessment + Exposure Analysis}
\]
Step 2: Checking the options.
Multi-hazard assessment is part of risk assessment because many disasters may affect the same region.
Vulnerability assessment is a core part of risk assessment.
Elements at risk refer to people, buildings, infrastructure, and resources exposed to hazards.
Step 3: Identifying what does not directly come under risk assessment.
Cost-benefit assessment is mainly an economic evaluation technique. It compares the cost of a project or intervention with its benefits. It is not a basic component of risk assessment.
Therefore, the correct answer is Cost-benefit assessment.