What observation shows us that hydrogen bonding is quite strong?

A
There is hydrogen bonding, which is due to the fast motion and collisions of the gas particles.

B
Water has a much higher boiling point compared with similar type of molecules, so we can make the assumption that there is hydrogen bonding present.

C
Water has special properties and it boils at 100 degrees Celsius, due to the strong ionic bonds present in water.

D
Heating water to the boiling point allows for bonds to strengthen together and bond with other atoms.