Answer:
B. Air is a good insulator of heat.
Step-by-step explanation:
The right index finger felt warmer than left index finger because air is good insulator of heat. This is because for heat transfer via conduction, the molecules vibrate and collide with neighboring molecules and transfer energy. Since, the air molecules are very loosely packed, conduction of heat is very slow and difficult.
As we know, heat transfers from hotter body to colder body, the heat transferred from left index finger through solid balloon piece to ice water. But, in right index finger had air filled balloon which is not a good conductor of heat and hence, the finger was warmer.