A thermocouple shows an e.m.f. of 5.00 mV with one of its junctions at 0 °C and the other at 100 °C. If the 100 °C junction is taken out of the boiling water and placed in a glass of water having temperature same as the room temperature (assume room temperature in this case = 25 °C), the e.m.f. registered on thermocouple would be

• A. 5 mV
• B. 1.25 mV
• C. 20 mV
• D. 10 mV