Introduction:
In the field of electrical engineering, MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) are widely used in integrated circuits (ICs) for various applications. MOSFETs can be categorized into two types: nMOS (n-channel MOSFET) and pMOS (p-channel MOSFET). CMOS (Complementary Metal-Oxide-Semiconductor) and BiCMOS (Bipolar-CMOS) are also commonly used technologies in ICs. Among these, the nMOS, pMOS, CMOS, and BiCMOS technologies differ in terms of their structure, operation, and area occupied.

Explanation:
- nMOS:
nMOS is a type of MOSFET that uses an n-channel for conduction. It consists of a source, a drain, and a gate terminal. When a positive voltage is applied to the gate terminal, it creates an electric field that attracts electrons from the source to the drain, allowing current flow. In nMOS technology, the transistors are typically implemented using n-doped silicon, which requires more area compared to pMOS technology.

- pMOS:
pMOS is another type of MOSFET that uses a p-channel for conduction. It also consists of a source, a drain, and a gate terminal. When a negative voltage is applied to the gate terminal, it creates an electric field that attracts holes from the source to the drain, allowing current flow. In pMOS technology, the transistors are typically implemented using p-doped silicon, which requires more area compared to nMOS technology.

- CMOS:
CMOS technology combines both nMOS and pMOS transistors in a complementary configuration. It uses a combination of nMOS and pMOS transistors to achieve low power consumption, high noise immunity, and high packing density. CMOS technology requires both n-doped and p-doped silicon regions, which results in a higher area requirement compared to nMOS or pMOS technology alone.

- BiCMOS:
BiCMOS technology combines bipolar junction transistors (BJTs) with CMOS technology. It offers the advantages of both bipolar and CMOS technologies, such as high speed and low power consumption. However, BiCMOS technology typically requires a larger area compared to CMOS technology due to the integration of bipolar transistors.

Conclusion:
Among the given options, the nMOS technology occupies lesser area compared to pMOS, CMOS, and BiCMOS technologies. This is because nMOS transistors can be implemented using n-doped silicon, which requires less area compared to p-doped silicon used in pMOS technology. Additionally, CMOS and BiCMOS technologies require both n-doped and p-doped silicon regions, further increasing the area requirement. Therefore, the correct answer is option 'A' - nMOS.