Incorrect Statement about Fourth Generation Computers: c) Their manufacturing process required manual assembly of individual components into electronic circuits.

Explanation:
The fourth generation of computers was developed in the late 1970s and continued into the early 1990s. These computers were a significant advancement over the previous generations in terms of size, performance, and capabilities. They introduced several new features and technologies that made them more powerful and efficient.

Larger Primary and Secondary Storage Capacity:
- The statement in option a) is correct. Fourth generation computers had larger primary and secondary storage capacity compared to third generation computers.
- This was made possible by the development of smaller and more efficient integrated circuits (ICs) and semiconductor memory technologies such as dynamic random-access memory (DRAM).
- These advancements allowed for increased memory capacity, which in turn enabled more complex and resource-intensive applications to be run on these computers.

General Purpose Machines:
- The statement in option b) is correct. Fourth generation computers were general-purpose machines, meaning they were designed to perform a wide range of tasks and applications.
- They were capable of executing various software programs and could be used for tasks such as word processing, data analysis, graphics, and gaming.
- This versatility made them suitable for both personal and business use.

Less Power Consumption:
- The statement in option d) is correct. Fourth generation computers consumed less power than their third generation counterparts.
- This was primarily due to advancements in semiconductor technology, which allowed for the development of more energy-efficient microprocessors and electronic components.
- The reduced power consumption not only made these computers more environmentally friendly but also helped in reducing electricity costs.

Automated Manufacturing Process:
- The statement in option c) is incorrect. The manufacturing process of fourth generation computers did not require manual assembly of individual components into electronic circuits.
- Instead, the development of integrated circuits (ICs) and printed circuit boards (PCBs) enabled the automated production of electronic circuits.
- ICs integrated multiple electronic components onto a single chip, reducing the need for manual assembly.
- PCBs provided a platform for connecting and interconnecting these ICs and other electronic components, further streamlining the manufacturing process.

In conclusion, the incorrect statement about fourth generation computers is c) Their manufacturing process required manual assembly of individual components into electronic circuits. The manufacturing process of fourth generation computers was automated, thanks to the advancements in integrated circuit technology and printed circuit board manufacturing.