Answer: The correct answer is Option D.
Explanation:
Isotopes are defined as the chemical species which have same atomic number but differ in mass number.
Stable isotopes are defined as isotopes which does not undergo decay process. They have more half life. They are known as non-radioactive isotopes.
Radioactive isotopes are defined as the isotopes which undergo decay processes very easily. They have very short half life. They are usually the isotopes of heavier elements.
Hence, the correct answer is Option D.
