Answer:
11B
Step-by-step explanation:
When 10B absorbs a neutron, it becomes the unstable isotope 11B, which quickly undergoes beta decay to form the stable isotope 11C. In this process, a neutron in the 10B nucleus is transformed into a proton, which increases the atomic number of the isotope from 5 to 6. The beta decay of 11B involves the emission of an electron (beta particle), which is produced when a neutron in the nucleus decays into a proton and an electron.