which answer shows a balanced nuclear equation for the beta decay of potassium-42

i)       . ⁴² ₁₉K  −→ ⁴²₂₀Ca + ⁰_-1e  

ii)    ⁴³ ₁₉K  −→ ⁴³₂₀Ca + ⁰_-1e  

iii)  ⁴³ ₁₉K  −→ ⁴³₁₈Ar+ ⁰_-1e  

iv)  ⁴² ₁₉K  −→ ⁴²₁₈Ar+ ⁰_-1e  

v)    ⁴³ ₁₉K  −→ ⁴¹₁₈Ar+ ⁰_-1e  

the  balanced nuclear equation is ⁴² ₁₉K  −→ ⁴²₂₀Ca + ⁰_-1e.