#### Answer

b, c, and e

#### Work Step by Step

(a) 100101101 No of 1’s = 5 Since no of 1’s are odd therefore in this either$(no\ error\ occurred)$ or errors occurred in even no of bits as odd parity is used. So we can’t detect whether an error occurred or not.
(b) 100000001 No of 1’s = 2 Since no of 1’s are even therefore in this $(error\ occurred)$ as odd parity is used.
(c) 000000000 No of 1’s = 0 Since no of 1’s are even therefore in this $(error\ occurred)$ as odd parity is used.
(d) 111000000 No of 1’s = 3 Since no of 1’s are odd therefore in this either $(no\ error\ occurred)$ or errors occurred in even no of bits as odd parity is used. So we can’t detect whether an error occurred or not.
(e) 011111111 No of 1’s = 8 Since no of 1’s are even therefore in this $(error\ occurred)$ as odd parity is used.