3 votes 3 votes For class B network, all even bit positions are selected for subnet mask bits. What is the possible subnet mask? (A) 255.25.170.170 (B) 255.255.85.85 (C) 255.255.255.240 (D) None Computer Networks computer-networks subnetting + – shraddha priya asked Oct 22, 2017 shraddha priya 769 views answer comment Share Follow See all 5 Comments See all 5 5 Comments reply Angkit commented Oct 22, 2017 i edited by Angkit Oct 22, 2017 reply Follow Share (A) 255.255.170.170 ? 0 votes 0 votes saxena0612 commented Oct 22, 2017 i edited by saxena0612 Oct 22, 2017 reply Follow Share Both option a and b are correct because if you consider MSB of a octet as 0th bit then answer is a else its bEDI for ex :255.255.01010101.01010101= 255.255.85.85 Considering LSB as 0th place. EDIT: Thanks @ rishi71662data4 for pointing out ! I didnt see 25 in second octet and assumed it as 255 Thus it can`t be right answer Option B is correct if it would have been 255 then above Statement of mine is applicable, 0 votes 0 votes shraddha priya commented Oct 22, 2017 reply Follow Share Answer is given as option B but i too think both A and B are correct answers. 0 votes 0 votes rishi71662data4 commented Oct 22, 2017 reply Follow Share How can option A be correct ? It is a class B network, therefore we have 16 Most Significant bits in Network ID part. Remaining 16 bits are for host ID. Subnet Mask is all 1s for Network ID part. There subnet mask has to start like 255.255.something.someting. That "something" will depend on the number of subnet mask. From the given option, only B looks correct . 0 votes 0 votes akb1115 commented Oct 22, 2017 reply Follow Share I think there is a typo in option A 255.25.170.170 1 votes 1 votes Please log in or register to add a comment.