Answer: answer is a) an attractive force that usually involves a polarly-bonded hydrogen atom and another polarly-bonded atom with a partial negative charge
Explanation: hydrogen bond is a special type of bonding that closely resembles an ionic bond. It involves hydrogen atom and another highly electronegative atom, this bond is due to the the attraction between the slight positive charge on the hydrogen and the slight negative charge on the pairing atom.
Note that electron is not transfered as in ionic bonding.
Molucules with hydrogen bonding between their atoms includes water, hydrogen fluoride and ammonia.