Which of the following is not emitted during the radioactive decay of a radioactive element?

In gamma ray emission from a nucleus,

Actinium $231$,${}^{231}Ac_{89}$,emits in succession two $\beta^-$ particles,four $\alpha$ particles,one $\beta^-$ particle,and one $\alpha$ particle,plus several $\gamma$ rays. What is the resultant isotope?

Curie is a unit of

If a nucleus $P$ converts into a nucleus $Q$ by the decay of one alpha particle and two $\beta^{-}$ particles, then the nuclei $P$ and $Q$ are

In medicine,to destroy cancer cells . . . . . . rays are used.