With reference to the no-arbitrage approach to valuing a European option using a one-step binomial we: 27 Not yet Marked Flag Select one: O a choose probabilities for the branches of the tree so that the expected return on the stock equals the risk-free rate. Ob calculate probabilities for the branches of the tree using the formula Oc set up a portfolio consisting of a position in the option and the stock that is riskless. Od set up two portfolios consisting of a loan and positions in a stock, put and call options with the same payoffs. Oe. all of the above