Answer: Option (a) is the correct answer.
Step-by-step explanation:
Usually when freezing occurs then molecules of a substance come closer to each other. But there is an exception with water because when temperature of water reaches at less than 4 degree celsius then its atoms start to move apart from each other.
As a result, there occurs a breakage of hydrogen bonding. Due to this volume of ice increases and hence, there will be decrease in its density. This also make ice to float on water.
Thus, we can conclude that as water freezes its hydrogen bonds break apart.