Consider a nucleus that undergoes decay. (a) Is the radius of the resulting daughter nucleus greater

Question:

Consider a nucleus that undergoes α decay.
(a) Is the radius of the resulting daughter nucleus greater than, less than, or equal to the radius of the original nucleus?
(b) Choose the best explanation from among the following:
I. The decay adds an alpha particle to the nucleus, causing its radius to increase.
II. When the nucleus undergoes α decay it ejects two neutrons and two protons. This decreases the number of nucleons in the nucleus, and therefore its radius will decrease.
III. An α decay leaves the number of nucleons unchanged. As a result, the radius of the nucleus stays the same.