Final answer:
The Office of the Public Guardian and Trustee is the government department that deals with the Substitute Decisions Act, concerning adults who cannot make decisions for themselves.
Step-by-step explanation:
The Office of the Public Guardian and Trustee (PGT) is the government department that deals with matters related to the Substitute Decisions Act (SDA). The SDA is an act that governs decisions made on behalf of adults who are not able to make decisions about their own property or personal care. While the information provided about the solicitor general's role is related to legal proceedings, it does not directly pertain to the Office of the PGT or the Substitute Decisions Act.