[calmcoconut]

Summary

This PR improves the quality of wrong answer choices (distractors) across 11 multiple-choice questions in Chapter 5. The goal is to ensure no answer can be eliminated by tone or plausibility alone — every option should require actual content knowledge to dismiss.

Problem

Several distractors were "obviously absurd" — referencing physical hardware lifespans, gibberish CPU operations, or logical impossibilities (e.g., "transmit raw memory references over a network"). These made the correct answer identifiable by process of elimination without knowing the material.

Changes by Question

Question	Distractor(s) Changed	Replacement Strategy
Q1 (Language-specific serialization)	C, D	Replaced with real but subtly wrong claims about versioning and self-documentation
Q4 (Protobuf payload size)	D	Replaced gibberish float claim with plausible "delta encoding" wrong answer
Q5 (Protobuf removed tag rule)	D	Replaced "shift tag numbers" with a tempting but wrong migration script answer
Q7 (Avro vs Protobuf payload)	C, D	Replaced with near-miss answers about per-record schema prefix and Avro-uses-tags confusion
Q8 (Avro schema resolution)	D	Replaced brute-force guess with plausible embedded version-tag lookup answer
Q10 (Data outlives code)	A, C	Replaced hardware/SSD lifespan nonsense with real distributed systems concerns
Q13 (DB query vs service API)	A	Replaced write-only restriction nonsense with inverted reality (APIs expose full schema)
Q14 (RPC location transparency)	A	Replaced C++ requirement nonsense with real compile-time coupling concern
Q16 (Durable execution purpose)	A, C	Replaced index rebuild / encryption nonsense with plausible distributed locking and state caching
Q17 (Durable execution reorder)	C, D	Replaced CPU vectorization / cached binary nonsense with realistic operator-pause and drain behaviors
Q19 (Message broker advantage)	A	Replaced memory reference nonsense with plausible but wrong exactly-once claim
Q21 (CSV nested structures)	question reworded, D	Q reworded to be harder; swapped YAML for MessagePack as a more credible distractor
Q22 (REST API versioning)	A, C	Replaced purge-records and TCP port nonsense with TLS negotiation and body-field versioning
Q26 (Avro field backward compat)	C	Replaced capital-letter nonsense with near-miss union type answer

No Logic Changes

• All correct answers (correct: 1) are unchanged
• All explanations, flashcards, and modelAnswer fields are unchanged
• No UI or app logic was modified