Contract Lifecycle: Design, Development, and Deployment BDC Practice Questions (Page 6)

Questions 26–30

1. 26expert · hard

   A developer is deploying a contract to the Ethereum mainnet using Hardhat. The deployment script uses `ethers.getContractFactory('MyContract')` and then `factory.deploy()`. The deployment fails with an error 'insufficient funds for gas * price + value'. What is the most likely cause?

   • AThe RPC URL is incorrect.
   • BThe contract bytecode is too large.
   • CThe contract has a compilation error.
   • DThe account used for deployment does not have enough ETH to cover the gas cost.
   Reveal Solution Discussion Select an answer first
2. 27foundation · easy

   What is required to deploy a smart contract to the Ethereum mainnet?

   • AA funded account with real Ether to pay for gas fees.
   • BA local Ethereum node running in mining mode.
   • CA free API key from Infura to access the network.
   • DA testnet Ether faucet to obtain funds for the deployment.
   Reveal Solution Discussion Select an answer first
4. 28foundation · easy

   Which tool is commonly used to manage project dependencies, compile Solidity code, and run tests in a Hardhat project?

   • Anpm (Node Package Manager)
   • BGanache
   • CRemix IDE
   • Dsolc
   Reveal Solution Discussion Select an answer first
5. 29expert · hard

   A developer is deploying a contract to the Ethereum mainnet and wants to ensure that the deployment transaction is not front-run by bots that might interact with the contract before initialization. Which deployment strategy is most effective?

   • AUse a private transaction pool to hide the deployment transaction
   • BDeploy the contract and then call an initialize function in a separate transaction
   • CDeploy the contract with a constructor that sets the owner and initializes all critical state in the same transaction
   • DDeploy with a high gas price to ensure the transaction is mined first
   Reveal Solution Discussion Select an answer first
6. 30expert · hard

   A developer is designing a contract that handles user funds and wants to prevent reentrancy attacks. Which approach is the most robust and recommended?

   • AUse `require(msg.sender == tx.origin)` to ensure only EOAs can call.
   • BMake all functions `internal` to prevent external calls.
   • CUse a high gas limit on all functions.
   • DUse a reentrancy guard modifier that sets a lock before any external call and releases it after.
   Reveal Solution Discussion Select an answer first