Which type of engine in Hyperledger Burrow deals with executing smart contracts?

The smart contract application engine in Hyperledger Burrow is responsible for executing smart contracts. This engine is designed to interpret and execute the code written in the smart contracts, managing state transitions in response to the smart contracts' functions.

This engine operates in a manner that allows it to interact with the blockchain's overall architecture effectively, ensuring that smart contracts are executed in a secure and deterministic way. By isolating the execution logic of smart contracts, it provides a focused environment where contract execution can be reliably managed and fulfilled.

In contrast, the other options serve different purposes within the blockchain ecosystem. The consensus engine oversees the agreement among network participants on the state of the blockchain, ensuring all nodes have the same version of the ledger. The network stack engine manages networking protocols and ensures seamless communication between peers in the network. The storage engine, on the other hand, is responsible for persisting the blockchain data and smart contract states. While all these components are crucial for the functionality of Hyperledger Burrow, it is the smart contract application engine that specifically handles the execution of code within smart contracts.