I'm not sure how I got b and d wrong, can someone help?

A salesman normally makes a sale (closes) on 75% of his presentations. Assuming the presentations are independent, find the probability of each of the following. a) He fails to close for the first time on his fourth attempt. b) He closes his first presentation on his third attempt. c) The first presentation he closes will be on his second attempt. d) The first presentation he closes will be on one of his first three attempts. . . . a) The probability he fails to close for the first time on his fourth attempt is 0.1055. (Round to four decimal places as needed.) b) The probability he closes his first presentation on his third attempt is 0.0469. (Round to four decimal places as needed.) c) The probability the first presentation he closes will be on his second attempt is 0.1875 . (Round to four decimal places as needed.) d) The probability the first presentation he closes will be on one of his first three attempts is 0.9844 (Round to four decimal places as needed.)