Of the three independent events `E_1, E_2 and E_3,` the probability that only `E_1` occurs is `alpha,` only `E_2` occurs is `beta` and only `E_3` occurs is `gamma.` Let the probability p that none of events `E_1, E_2 and E_3` occurs satisfy the equations `(alpha-2beta), p=alphabeta and (beta-3gamma) p=2beta gamma.` All the given probabilities are assumed to lie in the interval `(0,1).` Then,`(probability of occurrence of E_1) / (probability of occurrence of E_3)` is equal to

Answer

b