For each of the following reactions establish whether it is allowed or not; if it is not, give the reasons.

(a) p →  n+e⁺;

(b) μ⁺→ ν_μ + e⁺;

(c) e⁺+e→  ν_μ + ν_μ;

(d) ν_μ + p →  μ⁺+ n

(e) ν_μ + n →  μ^- + p;

(f) ν_μ + n →  e^-+ p;

(g) e⁺+n →  p + νe;

(h) e^-+ p → n + νe.