The correct option is B β−1,→v (antineutrino)
Beta decay is a process in which unstable atoms undergoes radioactivity to become more stable.
There are two types of beta decay, beta-minus and beta-plus. During beta-minus decay, a neutron in an atom's nucleus turns into a proton, an electron and an antineutrino. The electron and antineutrino fly away from the nucleus, which now has one more proton than it started with. Since an atom gains a proton during beta-minus decay, it changes from one element to another.