Solidity Practice Test
Solidity Solidity DeFi and Token Standards
What is the ERC-20 `allowance` mechanism and what attack does it enable?
Select your answer
A
It lets owners approve spenders to transfer tokens, but a race condition allows double-spending if approval amount is changed
B
It prevents token transfers above a daily limit
C
It is a blacklist mechanism to block specific addresses
D
It enables the contract to burn tokens automatically
Hint
