What happens during radioactive decay?
a) daughter isotopes turn into energy.
b) daughter isotopes turn into parent isotopes.
c) parent isotopes turn into daughter isotopes.
d) energy turns into daughter isotopes.
e) parent isotopes turn into energy.

(c) parent isotopes turn into daughter isotopes

Explanation:

Whenever there is a radioactive decay then there is change of parent isotope into daughter isotopes. Parent isotopes is that which is present before the decay and daughter isotopes is that which is formed after the decay.

so the correct option will be option (c) as in option (c) it is given that parent isotopes turn into daughter isotopes

i think its 100

i hope this !