The Half-Life of a Radioactive Element Is the Period of Time

The half-life of a radioactive element is the period of time required:

A) to convert half of a given mass into radioisotopes.
B) to extract one-half of the energy from the Earth's uranium supply.
C) for one half of the total amount of a radioactive substance to change into a different material.
D) for the sun to use up one-half of its available atomic resources.
E) None of these