If a student practises continuously but does not distinguish the causes of different mistakes, which skill is weak?

Correct answer: Error-cause analysis and classification

Practice becomes more effective when mistakes are diagnosed instead of being treated as one general problem. A student may make errors because of weak understanding, incorrect procedure, poor time management, or haste; each cause needs a different remedy. Separating and grouping these causes is error-cause analysis and classification. Thus, option C is the relevant skill.