A smart contract is designed to release payments to a supplier only after a shipment's arrival is confirmed by an IoT sensor. The blockchain network itself cannot directly access data from the IoT sensor. Which of the following is required to securely and reliably feed the external data to the smart contract?
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A
A centralized server owned by the shipping company
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B
A blockchain oracle
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C
A direct API call from the smart contract to the IoT device
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D
Manual data entry by a network administrator