Stock Z is trading at $50 today. In one year, the value will go either up to $62.50 or down to $40. A call option on Z with exactly one year to expiration has a strike price of $55. Inflation is high, so the interest rate is 10% per year. Find the delta of the call option using binomial approach.

a. 0.33

b. 0.67

c. 0.25

d. 1.05