Which of the following radioisotopes is used as anticancerous?

Which of the following processes does not occur via $\alpha$-decay?

If a radioactive isotope with atomic number $A$ and mass number $M$ emits an $\alpha$-particle,the atomic number and mass number of that new isotope will become:

During a negative $\beta$-decay:

The penetrating power of an $\alpha$-particle is:

The carbon dating is based on