Answer:
Option (1)
Step-by-step explanation:
The parent radioactive isotopes are those that are comprised of a unstable nucleus, which continuous decay and emits harmful radiations and after consecutive half lives, their original composition reduces to half and so on. It slowly converts into a more stable one, where the nucleus is more stable and emits lesser amount of radiations. These are known as the daughter isotope..
Thus, the daughter isotopes are comprised of more stable nucleus in comparison to the parent isotopes.
Hence, the correct answer is option (1).