Final answer:
D.) blockchain. The technology designed to prevent the alteration of software once constructed is blockchain, which secures data with cryptographic links between blocks and requires network consensus for modifications.
Step-by-step explanation:
The technology that attempts to ensure that, once the software is constructed, it cannot be altered is D) blockchain. Blockchain is a distributed database that maintains a continuously growing list of records, called blocks, which are linked and secured using cryptography.
Each block contains a cryptographic hash of the previous block, a timestamp, and transaction data, effectively creating a chain of blocks with a high level of security.
Blockchain's design is inherently resistant to modification of the data. Once recorded, the data in any given block cannot be altered retroactively without the alteration of all subsequent blocks, which requires a consensus of the network majority. This makes blockchain an important technology for applications where immutable records are crucial, such as in cryptocurrencies like Bitcoin.