Teacher:In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.
Teacher: Now, understand the problem? Solve this instance: Question: How many of the particles emitted in the process of transmuting Np to Pu have a charge? Passage:Heavy-water reactors may pose a greater risk of nuclear proliferation versus comparable light-water reactors due to the low neutron absorption properties of heavy water, discovered in 1937 by Hans von Halban and Otto Frisch. Occasionally, when an atom of U is exposed to neutron radiation, its nucleus will capture a neutron, changing it to U. The U then rapidly undergoes two β decays — both emitting an electron and an antineutrino, the first one transmuting the U into Np, and the second one transmuting the Np into Pu. Although this process takes place with other moderators such as ultra-pure graphite or beryllium, heavy water is by far the best. 
 Links: a. Nuclear proliferation b. Neutron c. Uranium-238 d. Electron
Student:
d