Final answer:
Resources always exceed reserves because reserves are a subset of resources that are economically recoverable with current technology, while resources include all known quantities, whether currently recoverable or not (A).
Step-by-step explanation:
When comparing the amount in resources and reserves for a particular resource, option A is correct: Resources are always greater than reserves. Resources are the total amount of a substance that exists in the ground and includes what is known to exist and can be used now or in the future with current technology.
On the other hand, reserves are a subset of resources; they are the amount of a resource that is known to exist and is recoverable under current economic conditions and present-day technological abilities. Therefore, since reserves must meet certain conditions to be economically viable, they are always less than the total estimated resources.