A digital signature directly addresses both confidentiality and integrity of the CIA triad. It does not directly address availability, which is what denial-of-service attacks.
The other answers are not correct because:
“nonrepudiation” is not correct because a digital signature can provide for nonrepudiation. “authentication” is not correct because a digital signature can be used as an authentication mechanism “data integrity” is not correct because a digital signature does verify data integrity (as part of nonrepudiation)
References: Official ISC2 Guide page: 227 & 265 All in One Third Edition page: 648