The correct answer is: A. Is a bad conductor of heat so only inner surface expands.
When a hot liquid is poured into a thick glass tumbler, the inner surface of the glass comes into contact with the hot liquid and expands. The outer surface of the glass, however, is not in contact with the hot liquid and does not expand as much. This difference in expansion causes the glass to crack.
Option B is incorrect because glass does not have a high temperature coefficient of expansion. In fact, glass has a relatively low temperature coefficient of expansion. This means that it does not expand very much when heated.
Option C is incorrect because glass has a relatively high specific heat. This means that it takes a lot of heat to raise the temperature of glass.
Option D is incorrect because glass has a relatively low temperature coefficient of expansion. This means that it does not expand very much when heated.
In conclusion, the correct answer is: A. Is a bad conductor of heat so only inner surface expands.