Easy Problem

From the figure it can be seen that the number of posts will be 1 more than the number of chains used in the fence.
Let x number of chains and posts be used.
6 in. = 0.5 feet
Then length of the fence = 5.5x + 0.5. Now look at the given answer choices one by one.
(A) 17 = 5.5x + 0.5 implies x = 3, which is the possible length of fence. So, (A) is not the correct answer.
(B) 28 = 5.5x + 0.5 implies x = 5, which is the possible length of fence. So, (B) is not the correct answer.
(C) 35 = 5.5x + 0.5 implies x = 6.2727..., which is the not the possible length of fence. So, [spoiler](C) is the correct answer.[/spoiler]