You want to manage temperature and humidity only at the facility level in your data...

ASHRAE recommends temperature and humidity be measured in the cold aisle, in front of racks, at approximately 1.5 m above the floor (average human working height) and 0.3–0.5 m from the rack face. This location captures the environmental conditions experienced at the IT equipment air intake, while still representing facility-level conditions (not single device-level).

Option A and C (at 50 mm intake/rear) are too close to individual servers and suited only for rack-level monitoring, not facility monitoring.

Option D (rear measurement) reflects exhaust air, not intake, and thus cannot be used to control environmental setpoints.

Maintaining measurement at standardized facility locations allows comparisons against ASHRAE’s recommended and allowable ranges (18–27 °C for Class A1 environments, 40–60% RH).