Smart Contracts and dApp Design for Business BBLC Practice Questions (Page 5)

Questions 21–25

1. 21expert · hard

   A legal tech company is deploying a smart contract for notarization services. The contract must be upgradeable to accommodate changes in legal requirements, but the company also wants to maintain a tamper-proof audit trail. Which approach best satisfies both requirements?

   • AUse a proxy contract that delegates calls to an implementation contract, allowing upgrades while preserving the contract address.
   • BDeploy a new contract each time requirements change and migrate all data.
   • CMake the contract immutable and require all changes to be handled off-chain.
   • DUse a multi-signature wallet to manually change the contract's code.
   Reveal Solution Discussion Select an answer first
2. 22foundation · easy

   A business wants to deploy a smart contract that manages a multi-step approval workflow, where each step must occur in a specific order. Which design pattern is most appropriate?

   • AState Machine
   • BProxy
   • CPull Payment
   • DAccess Restriction
   Reveal Solution Discussion Select an answer first
4. 23application · medium

   A decentralized voting platform wants to ensure that each registered voter can vote only once and that votes cannot be altered after submission. Which smart contract design pattern is most suitable?

   • AA pattern that stores votes in a centralized database and only uses the blockchain for hashes.
   • BA pattern that uses a random selection to determine which votes are counted.
   • CA mapping that tracks whether each address has voted, and a function that records the vote permanently.
   • DA pattern that allows voters to change their vote multiple times before the deadline.
   Reveal Solution Discussion Select an answer first
5. 24application · medium

   A gaming company is developing a dApp where players can trade in-game items as NFTs. The team wants to ensure that the frontend always reflects the latest ownership data without requiring manual refreshes. Which dApp component should they implement?

   • AA polling mechanism that checks the blockchain every hour.
   • BA webhook that notifies the frontend whenever a transaction is mined.
   • CA centralized database that stores ownership data and is updated by the backend.
   • DA subscription to blockchain events using a library like web3.js or ethers.js.
   Reveal Solution Discussion Select an answer first
6. 25application · medium

   A real estate company wants to automate the escrow process for property sales. The smart contract should hold the buyer's funds and release them to the seller only when both parties confirm the transfer of ownership. Which smart contract feature is essential for this business process?

   • AA self-destruct function that allows the contract to be deleted after the sale.
   • BA time-based lock that releases funds after a fixed period regardless of confirmations.
   • CA multi-party approval mechanism that requires confirmations from both buyer and seller before releasing funds.
   • DA random number generator to determine the sale price.
   Reveal Solution Discussion Select an answer first