A nucleus of uranium-238 (92238U^{238}_{92}\text{U}92238U) decays through a series of alpha (α\alphaα) and beta-minus (β−\beta^-β−) emissions to form a stable nucleus of radium-226 (88226Ra^{226}_{88}\text{Ra}88226Ra).
Which sequence of decays could achieve this transition?
α+α+α+β−\alpha + \alpha + \alpha + \beta^-α+α+α+β−
α+α+α+β−+β−\alpha + \alpha + \alpha + \beta^- + \beta^-α+α+α+β−+β−
α+α+β−+β−\alpha + \alpha + \beta^- + \beta^-α+α+β−+β−
α+α+α+α+β−+β−\alpha + \alpha + \alpha + \alpha + \beta^- + \beta^-α+α+α+α+β−+β−
