*Question E8A10:
What is the purpose of a low-pass filter used at the output of a digital-to-analog converter?*  

*Correct Answer is  C: Remove spurious sampling artifacts from the output signal*  

### AI Response: (may contain errors)  

The correct answer to the question about the purpose of a low-pass filter (LPF) used at the output of a digital-to-analog converter (DAC) is:

**C: Remove spurious sampling artifacts from the output signal.**

### Explanation of the Correct Answer:
- **Low-Pass Filter Functionality**: A low-pass filter allows signals with a frequency lower than a certain cutoff frequency to pass through while attenuating frequencies higher than that cutoff. In the context of a DAC, the output signal can contain high-frequency components (spurious artifacts) due to the discrete nature of the digital signal. The LPF smooths out these artifacts, resulting in a cleaner analog output.

### Why the Other Choices are Incorrect:
- **A: Lower the input bandwidth to increase the effective resolution**: 
  - This statement is misleading. While reducing bandwidth can improve signal quality, it does not directly increase the effective resolution of the DAC. Effective resolution is more related to the number of bits in the digital signal rather than the bandwidth.

- **B: Improve accuracy by removing out-of-sequence codes from the input**: 
  - This choice is incorrect because low-pass filters do not address the issue of out-of-sequence codes. Out-of-sequence codes are related to the digital input signal's integrity and timing, not something that can be corrected by filtering the output.

- **D: All these choices are correct**: 
  - Since choices A and B are incorrect, this option cannot be correct either.

### Summary:
The primary role of a low-pass filter at the output of a DAC is to remove high-frequency noise and artifacts, ensuring a smooth and accurate analog signal. This is crucial for applications where signal integrity is important, such as audio and communication systems. 

In practice, the cutoff frequency of the LPF is typically set just above the maximum frequency of interest in the output signal to effectively filter out unwanted high-frequency components while preserving the desired signal.