1) is false because a neutron has a relative mass of 1 and a positron has a relative mass of 0 (It's the antimatter version of an electron - same mass, opposite charge).
2) is correct, because a beta particle has a relative mass of 0 (It's just an electron), and a neutron has a relative mass of 1.
3) is incorrect because an alpha particle has a relative mass of 4 (It's a Helium Nucleus) and a positron has a relative mass of 1.
4) is incorrect because an alpha particle has a relative mass of 4 and a beta particle has a relative mass of 0.
