Depending on the methodology employed in qualitative analysis, the categories may be described with words such as

Qualitative risk analysis uses expert judgment to categorize the probability and consequence of failure into descriptive levels. The most common descriptors are words like "High," "Medium," and "Low." However, to facilitate ranking and representation in a risk matrix, these descriptive categories are often assigned corresponding numerical values (e.g., 1 to 5). This allows for a more structured, albeit still qualitative, assessment. Therefore, the methodology can employ descriptive words, numerical descriptors, or a combination of both to define the risk categories. Options B and C are incorrect because they are overly restrictive.

B. High, medium or low only: This is incorrect because numerical descriptors are also commonly used in qualitative methodologies to rank the categories.
C. Numerical descriptors only: This is incorrect as the foundation of qualitative analysis is descriptive language; numbers are used to represent these descriptions.

1. American Petroleum Institute. (2016). API Standard 580, Risk-Based Inspection (3rd ed.). Section 9.2, "Qualitative Risk Analysis." The text explicitly states, "The categories may be described with words such as high, medium, or low, or may have numerical descriptors (e.g. 1, 2, 3, 4, 5)."