Final answer:
When a nuclide of 64/29 Cu absorbs a positron, it undergoes a process called positron emission and the resulting atom is 63/29 Cu.
Step-by-step explanation:
When a nuclide of 64/29 Cu absorbs a positron, it undergoes a process called positron emission. During this process, one of the protons in the nucleus is transformed into a neutron, resulting in a new atom. The resulting atom will have the same number of protons as the original atom, but one less proton. Therefore, the resulting atom will be 63/29 Cu, which is option B.