Practice Library
All MCQs
Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
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Correct Answer: B. An operating system manages hardware resources and provides services to applications
Explanation:
Operating systems coordinate processes, memory, storage, devices and user/application interfaces.
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Correct Answer: A. A transaction groups operations so consistency can be preserved across success or failure
Explanation:
Transaction properties help preserve consistent state when multiple operations must succeed together or be rolled back.
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Correct Answer: B. Routers forward packets between networks using destination information and routing decisions
Explanation:
Routing selects network paths and forwards packets toward their destination networks.
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Correct Answer: A. Users and processes should receive only the permissions necessary for their tasks
Explanation:
Limiting permissions reduces the impact of mistakes and compromised accounts.
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Correct Answer: A. DNS maps human-readable domain names to network-related records such as IP addresses
Explanation:
The Domain Name System is a distributed naming service used to resolve domains.
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Correct Answer: D. IP handles addressing and routing, while TCP provides reliable ordered delivery for a connection
Explanation:
The Internet protocol suite separates network-layer routing from transport-layer reliability.
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Correct Answer: A. A function packages reusable behaviour and parameters supply inputs to that behaviour
Explanation:
Functions support abstraction and reuse, while parameters pass values into a call.
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Correct Answer: B. Selection chooses among paths while iteration repeats a block under a condition
Explanation:
Branches choose execution paths; loops repeat work while their control condition allows it.
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Correct Answer: A. A data type constrains the values and operations valid for a variable
Explanation:
Types define representation and permitted operations, helping programs detect invalid use.
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Correct Answer: B. Testing seeks evidence about defects and behaviour but cannot prove the complete absence of defects
Explanation:
Testing samples behaviour against expectations; exhaustive proof is usually infeasible.
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Correct Answer: C. Encapsulation groups data with methods and controls access to internal state
Explanation:
Encapsulation supports modular design by hiding implementation details behind a defined interface.
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Correct Answer: B. A primary key uniquely identifies each row in a table
Explanation:
Primary-key values are unique and support reliable row identification and relationships.
