*Question E6C09:
What is used to design the configuration of a field-programmable gate array (FPGA)?*  

*Correct Answer is  B: Hardware description language (HDL)*  

### AI Response: (may contain errors)  

Field-programmable gate arrays (FPGAs) are integrated circuits that can be configured by the user after manufacturing. The configuration of an FPGA is typically done using a Hardware Description Language (HDL).

### Explanation:

1. **Correct Answer: B: Hardware description language (HDL)**
   - **Why it's correct:**  
     HDLs, such as VHDL or Verilog, are specialized programming languages used to describe the structure and behavior of electronic circuits. They allow designers to specify the logic functions and interconnections within an FPGA, enabling the creation of custom digital circuits.

2. **Why the other choices are incorrect:**
   - **A: Karnaugh maps**  
     Karnaugh maps are a method used to simplify Boolean algebra expressions, which is useful in designing logic circuits but not directly used for configuring FPGAs.
   
   - **C: An auto-router**  
     An auto-router is a tool used in PCB design to automatically route electrical connections between components. It is not used for FPGA configuration.
   
   - **D: Machine and assembly language**  
     Machine and assembly languages are low-level programming languages used for writing software that runs on processors. They are not used for configuring the hardware logic of FPGAs.

### Summary:
HDLs are essential for FPGA design because they provide a way to describe the desired logic and functionality of the circuit, which the FPGA can then implement. This makes option B the correct choice.