Ascientist observes that the particles emitted by a radioactive substance cannot be detected when the substance is enclosed in a thin sheet of paper. he thinks that the sample is polonium (po, atomic number 84) and that it is decaying to astatine (at, atomic number 85) by beta decay. which statement correctly assesses his conclusion?

a) it could be this reaction, because nuclear fission does not release particles.
b) it could be this reaction, because alpha particles are blocked by the paper.
c) it cannot be this reaction, because beta particles would penetrate the paper.
d) it cannot be this reaction, because gamma rays are blocked by paper.