What is the height of 1U of space in a server rack?

The height of 1U of space in a server rack is 1.75 inches. The term "U" refers to "rack units" and is a standardized unit of measurement used to specify the height of equipment designed for mounting in a 19-inch wide rack. One rack unit (1U) measures 1.75 inches in height, which allows for uniformity and standardization across different equipment types and manufacturers.

This standardization is essential in data centers to ensure that all hardware can fit properly within the racks and to optimize space utilization.

The other options do not align with the recognized standard for rack unit measurements; therefore, they do not represent the correct height of 1U.