Final answer:
Fluorine is the most reactive element with oxygen due to its status as the most powerful oxidizing agent among the known elements, surpassing the reactivity of hydrogen, sodium, and even oxygen itself.
Step-by-step explanation:
The element most reactive with oxygen among the given options is Fluorine (D). Fluorine is the most powerful oxidizing agent of the known elements and reacts quite vigorously. In fact, it oxidizes most other elements due to its high electronegativity and reactivity. Fluorine's remarkable reaction activity includes the ability to form binary fluorides with all elements, excluding the lighter noble gases, and even causing ignition upon contact with certain substances including water. This propensity makes it uniquely reactive with oxygen.
Although hydrogen also reacts explosively with oxygen, its reactivity is not as strong as fluorine's. When considering oxidation reactions, it is important to remember that while other elements such as sodium and oxygen do react with oxygen as well, they do not match the level of reactivity that fluorine exhibits.