He was a quick student - This means that Alexander ________.

The correct answer is Option D (was a fast learner).

Key Points:
• Core Language Concept Tested: The question primarily tests the candidate's understanding of idiomatic and contextual meanings of common adjectives within a reading comprehension passage.
• Why the Correct Option is Right: The official answer key marks option 4 as correct. In English, when the adjective 'quick' is applied to a student, a mind, or a thinker, it refers to cognitive speed, meaning the person grasps concepts rapidly. Therefore, "a quick student" means he was "a fast learner." This aligns perfectly with the passage's tone regarding his academic progression.
• Common Exam Traps and Pitfalls: MPSC often uses words with multiple meanings (polysemy) to confuse candidates. A common mistake is interpreting 'quick' literally as physical speed (option 1: reached school before his brothers) or chronological speed (option 2: reached the school-leaving age). These literal interpretations completely miss the contextual linguistic nuance.
• Elimination of Incorrect Options: Option 1 is a trap based on physical running. Option 2 relates to age, not learning ability. Option 3 ('lively') relates to temperament, not academic aptitude. Thus, by recognizing the standard English usage of 'quick' in academic contexts, we arrive safely at the correct choice.
• Preparation Strategy: For future exams, familiarize yourself with collocations and standard adjective-noun pairings in English, such as 'quick mind' or 'slow learner'.
• Key Takeaway: Remember: In academic contexts, a 'quick' student or a 'quick' mind refers to someone's intelligence and ability to learn fast, not their physical speed.