Final answer:
A very reactive element will react to form compounds in nature, not be found in its pure state, and have to be mined and refined for use.
Step-by-step explanation:
If an element is very reactive, then it will react with other elements to form compounds in nature. This reactivity means that the element is unlikely to be found in its pure form because it readily combines with other substances. For instance, alkali metals react quickly with oxygen and water, hence are always found in compound form. Reactive elements often require that they be mined as another substance and then processed or refined to be converted into their pure form for human use.
Therefore, the correct answer is (c) all of the above are true; a very reactive element will both react with other elements to form compounds and not be found in its pure form in nature. It will most likely have to be mined in the form of compounds and then converted into its pure form.