Answer:
Option B, The electronic thermometer was not calibrated correctly.
Step-by-step explanation:
Calibration is required when a relationship is to be established between a known standard unit and a new measuring device.
Since liquid thermometer is a standard device to measure temperature of a room, it is the electronic thermometer which might have been collaborated to convert measured electric pulses into degree Celsius.
There are rare chances of a standard device showing a wrong reading and hence it is the electronic thermometer that has not been collaborated well.
Thus, option B is correct.