The correct answer is A - Homomorphic encryption.
According to WGU Cybersecurity Architecture and Engineering (KFO1 / D488), homomorphic encryption allows computations to be performed directly on encrypted data without needing to decrypt it first. This ensures the confidentiality of the data even during processing.
SFE (B) allows two parties to jointly compute a function without revealing inputs but is not the same. SSL (C) secures communication channels. PIR (D) is for retrieving information privately, not computing on encrypted data.
Reference Extract from Study Guide:
"Homomorphic encryption allows operations on encrypted data, enabling secure processing by third parties without exposing underlying data."
- WGU Cybersecurity Architecture and Engineering (KFO1 / D488), Advanced Encryption Techniques