VHDL-AMS is the correct answer.

Explanation:
VHDL (Very High-Speed Integrated Circuit Hardware Description Language) is a hardware description language used in the field of electronic design automation to describe digital and mixed-signal systems. It is widely used for designing and simulating digital integrated circuits.

Analog and Mixed-Signal (AMS) systems deal with the design and simulation of systems that include both digital and analog components. These systems are becoming increasingly common in modern electronic designs.

VHDL-AMS is an extension of VHDL that allows designers to describe and simulate mixed-signal systems. It provides the capability to model analog and mixed-signal components along with digital components.

Advantages of VHDL-AMS:
- Integration of digital and analog components: VHDL-AMS allows designers to describe both digital and analog components in a single language, enabling the simulation of mixed-signal systems.
- Reusability: VHDL-AMS models can be reused across different designs, reducing the design time and effort.
- Verification: VHDL-AMS models can be used to verify the behavior and performance of mixed-signal systems before fabrication.
- Standardization: VHDL-AMS is an IEEE standard (IEEE 1076.1-1999), ensuring compatibility and interoperability across different tools and platforms.

Other options:
- System VHDL: System VHDL is not a valid term. It might be a typo or a misinterpretation of SystemVerilog, which is a hardware description and verification language.
- Verilog: Verilog is another hardware description language similar to VHDL, but it does not have an equivalent analog extension like VHDL-AMS.
- SystemVerilog: SystemVerilog is an extension of Verilog that includes additional features for verification. While it is widely used for digital design and verification, it does not have native support for analog modeling.

Therefore, the correct answer is VHDL-AMS, as it is the only option that represents an analog extension of VHDL.