A radioactive nucleus (initial mass number $$A$$ and atomic number $$Z$$) emits 3 $$\alpha$$-particles and 2 positrons. The ratio of number of neutrons to that of protons in the final nucleus will be

A

$$\frac{A - Z - 8}{Z - 4}$$

B

$$\frac{A - Z - 4}{Z - 8}$$

C

$$\frac{A - Z - 12}{Z - 4}$$

D

$$\frac{A - Z - 4}{Z - 2}$$