pls write out formula used to solve this equation

The current stock price of Alcoco is $70, and the stock does not pay dividends. The instantaneous risk-free rate of return is 6%. The instantaneous standard deviation of Alcoco's stock is 40%. You want to purchase a call option on this stock with an exercise price of $75 and an expiration date 30 days from now. Based on the BlackScholes OPM, the call option's delta will be .28 .31 .62 .70