The correct answer is B. Learning about the user's behavior and preferences. The uploaded study guide directly confirms this answer. Usability testing evaluates how representative users actually interact with a product, prototype, or workflow. Designers observe where users succeed, hesitate, misunderstand information, make errors, or adopt unexpected approaches. These behavioral observations reveal whether the experience aligns with users' mental models and expectations.
Option A contradicts proper usability-testing methodology. The objective is not to train participants to operate the interface correctly. Excessive instructions or coaching can contaminate the study because they prevent researchers from observing whether the design itself communicates what users need to know. The participant should generally attempt representative tasks while the researcher observes behavior and gathers feedback.
Option C describes a narrower comparative optimization technique associated more directly with A/B testing, where different interface variations are exposed to users and measured against a defined outcome. Usability testing instead concentrates on understanding why users experience particular successes or problems.
The critical examination distinction is therefore:
Usability testing = understand user behavior and usability problems.
A/B testing = compare alternative variations quantitatively.
That makes option B the only response aligned with the purpose of usability research.
Study Guide reference/topics: Usability testing, user behavior, user preferences, observational research, Testing.
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