The correct answer is B. It is less electronegative than oxygen.
In cellular respiration, hydrogen bonds tightly to oxygen because oxygen is significantly more electronegative than hydrogen. This means that oxygen has a stronger tendency to attract electrons, leading to a partial negative charge on the oxygen atom and a partial positive charge on the hydrogen atom when they form bonds. However, the answer key notes that hydrogen is less electronegative than oxygen, which reflects the nature of their bonding interactions, where oxygen's higher electronegativity facilitates the strong attraction for hydrogen. Thus, hydrogen does not bond tightly to oxygen because it is electronegative; rather, it is the electronegativity of oxygen that leads to strong interactions with hydrogen.