Increasing order (lowest first) for the values of em for electron (e),proton (p), neutron (n) and α-particles is

e/m for neutron =10​= 0e/m for alpha particle =42​= 0.5e/m for proton =11​=1e/m for electron =111850​=1850Note: e is the charge of the particle, m is the mass of a particle and the mass of an electron is 11850 times the mass of proton.Hence, the correct option is 2