Final answer:
Data signatures do not typically involve CAPTCHAs, however, they may be used together in certain applications to enhance data security.
Step-by-step explanation:
D. Depends on the application.
Data signatures are cryptographic digital signatures that are used to verify the authenticity and integrity of data. They are not typically associated with CAPTCHAs, which are used primarily to prevent automated bots from accessing a website or service. However, in certain applications where data security is a critical concern, CAPTCHAs may be used in conjunction with data signatures to ensure that the source of the data is legitimate.