Hello, help with the answer and how to please

IBM stock currently sells for 49 dollars per share. Over 12 month(s) the price will either go up by 11.5 percent or down by 7.0 percent. The risk-free rate of interest is 4.5 percent continuously compounded. If you are short one call option with strike price 51 and maturity 12 months how many shares of stock must you buy to establish a delta-neutral position? \begin{tabular}{l} \hline 0.22425 \\ \hline 0.40099 \\ \hline0.20075 \\ \hline 0.62718 \end{tabular}