正解:B
"For reliable identification of a person's face, Axis recommends a pixel density of at least 250 pixels per meter (80 pixels per foot) on the target area."
- Axis Communications, Design Tool: Pixel Density Recommendations
"Identification: 250 px/m - Needed to identify a person beyond reasonable doubt."
- Axis Communications Academy, Network Video Fundamentals, 2022
References:
Axis Communications - Pixel Density Guide
Axis Communications Academy, Network Video Fundamentals, 2022 (p. 62)