The correct option is
A β particles
Beta particle is high energy and high speed electron that is emitted from the radioactive element. Phosphorus-32 is a radioactive isotope of phosphorus. The electron is emitted from it in the form of beta particle. Sulfur-32 is formed as a result of emission of beta particles. Phosphorous-32 is used in medicine and molecular biology.
Thus, the correct answer is option B.