In radioactive decay process, the negatively charged emitted beta particles are:

• the electrons present inside the nucleus

• the electrons produced as a result  of the decay of neutrons inside the nucleus

• the electrons produced as a result of collisions between atoms

• the electrons produced as a result of collisions between atoms

B.

the electrons produced as a result  of the decay of neutrons inside the nucleus

Beta decay can involve the emission of either electrons or positirons. The electrons or positrons emitted in a beta-decay do not exist inside the nucleus. They are only createdat the time of emission, just as photons are created when an atom makes a  transition from higher to a lower energy state. 
In negative Beta decay a neutron in the nucleus is transformed into a proton, an electron and an antineutrino. Hence, in radioactive decay process, the negatively charged emitted beta process are the electrons produced as a result of the decay of neutrons present inside the nucleus.