The correct answer is option 'B': high packing density.

Explanation:
CMOS (Complementary Metal-Oxide-Semiconductor) is a widely used technology in the design and fabrication of integrated circuits (ICs). It offers several advantages over other technologies, including high packing density.

1. High Packing Density:
CMOS technology allows for high packing density, which means that a large number of transistors can be integrated into a small area on a chip. This is achieved by using a combination of both NMOS (N-type Metal-Oxide-Semiconductor) and PMOS (P-type Metal-Oxide-Semiconductor) transistors, which are complementary to each other. The compact layout of CMOS circuits enables the integration of a large number of components on a single chip, leading to higher functionality and performance.

2. Low Power Dissipation:
Another important advantage of CMOS technology is its low power dissipation. CMOS circuits consume very little power when compared to other technologies such as TTL (Transistor-Transistor Logic) or ECL (Emitter-Coupled Logic). This is because CMOS circuits only draw significant current when they are switching states, and the power dissipation is minimal when the circuits are in a static state. The low power consumption of CMOS circuits makes them suitable for use in portable devices and battery-powered applications.

3. High Noise Margin:
CMOS technology also offers a high noise margin, which refers to the ability of a circuit to tolerate noise signals without affecting its operation. CMOS circuits have a wide voltage swing, which allows for better noise immunity and robustness. This makes CMOS circuits less susceptible to noise interference and improves their reliability and performance.

4. Low Complexity:
Contrary to the given options, CMOS technology is known for its low complexity. The design and fabrication of CMOS circuits are relatively simpler compared to other technologies, such as Bipolar or BiCMOS (Bipolar Complementary Metal-Oxide-Semiconductor). CMOS circuits can be implemented using standard processes and are compatible with modern semiconductor manufacturing techniques, making them cost-effective and easier to produce.

In summary, CMOS technology offers several advantages, including high packing density, low power dissipation, high noise margin, and low complexity. However, the specific advantage highlighted in the given question is the high packing density, which allows for the integration of a large number of components on a single chip.