*Question T5C07:
What is the abbreviation for megahertz?*  

*Correct Answer is  D: MHz*  

### AI Response: (may contain errors)  

The correct abbreviation for megahertz is **MHz**. 

### Explanation of the Correct Answer:
- **MHz** stands for megahertz, which is a unit of frequency equal to one million hertz (cycles per second). 
- The "M" represents "mega," which is a metric prefix meaning one million, and the "Hz" stands for hertz.

### Why the Other Choices are Incorrect:
- **A: MH**: This abbreviation is incorrect because it omits the "z" for hertz. It does not represent any standard unit of frequency.
- **B: mh**: This is incorrect as it uses lowercase letters and does not follow the standard convention for metric prefixes. Additionally, "mh" does not represent any recognized unit.
- **C: Mhz**: This is incorrect because the "hz" should be in uppercase as "Hz." The correct format requires both parts of the abbreviation to be properly capitalized.

### Rules of Thumb:
- Always use uppercase letters for metric prefixes (e.g., M for mega, k for kilo).
- The correct format for frequency units should always include the appropriate capitalization (e.g., Hz for hertz).

By remembering these conventions, you can ensure that you use the correct abbreviations in your studies and on the exam.