C switch semantics: which statements are correct?\n1) switch is useful for testing a variable against a set of specific discrete values.\n2) switch is ideal for checking whether a value falls into arbitrary numeric ranges.\n3) Compilers often implement a jump table for switch cases (where appropriate).\n4) A break is not mandatory after every case label.

Introduction / Context:
Understanding when to use switch and how compilers may optimize it is foundational in C. Also important is recognizing fall-through and the role of break statements.

Given Data / Assumptions:

• Standard C switch that compares integral values (int, char, enum).
• No nonstandard compiler extensions (such as case ranges) are assumed.

Concept / Approach:
(1) True: switch shines when matching exact discrete values. (2) False in portable C: ranges require if-else chains unless you manually enumerate each value. (3) True in many implementations: compilers may create jump tables, binary searches, or chains depending on density—behavior is not guaranteed but is common. (4) True: break is not required; omitting it enables intentional fall-through, although you must manage control flow carefully.

Step-by-Step Solution:
Choose switch for enums or clustered integers.Use if-else for ranges (e.g., 0 <= x < 10, etc.).Insert break to avoid unintended fall-through unless fall-through is desired and documented.

Verification / Alternative check:
Examine -O2 disassembly for dense case sets to see jump-table generation; sparse sets often compile into comparisons.

Why Other Options Are Wrong:
Any option including (2) claims suitability for ranges, which is misleading. Options omitting (3) or (4) miss real-world compiler behavior and C control-flow rules.

Common Pitfalls:
Forgetting break; assuming jump-table generation is guaranteed; attempting case ranges without compiler extensions.

Final Answer:
1, 3, and 4