Introduction:
A sound card is a computer hardware component that is responsible for producing and processing audio signals. It is an essential component for any computer system to have the capability to play audio files. In this answer, we will explain why the correct answer to the given question is option 'A', which states that a sound card helps you listen to audio files.

Explanation:
A sound card performs several functions that enable a computer to produce and play audio files. Let's discuss these functions in detail:

1. Audio Input and Output:
- A sound card allows the computer to receive audio input from external devices such as microphones or line-in sources.
- It also enables the computer to produce audio output through speakers or headphones, allowing you to listen to audio files.

2. Digital-to-Analog Conversion (DAC):
- Sound cards have built-in digital-to-analog converters (DACs) that convert digital audio signals into analog signals.
- This conversion is necessary because audio files are stored digitally, but speakers produce sound in analog form.

3. Analog-to-Digital Conversion (ADC):
- Sound cards also have analog-to-digital converters (ADCs) that convert analog audio input signals into digital format.
- This allows the computer to process and store the audio data digitally.

4. Audio Processing:
- Sound cards have processors that can perform various audio processing tasks, such as equalization, surround sound effects, and noise cancellation.
- These processing capabilities enhance the audio quality and provide a better listening experience.

5. MIDI Support:
- Many sound cards also support Musical Instrument Digital Interface (MIDI) technology.
- MIDI allows computers to generate and control musical sounds using external devices like keyboards or synthesizers.

Conclusion:
In summary, a sound card is primarily responsible for enabling a computer to produce and play audio files. It performs functions like audio input and output, digital-to-analog and analog-to-digital conversion, audio processing, and MIDI support. Without a sound card, a computer would not be able to produce sound or play audio files. Therefore, the correct answer to the given question is option 'A', which states that a sound card helps you listen to audio files.