A town is laid out in a sure of side 1 kilometre, with six straight roads as shown. Each day the postman must walk the full length of every road at least once, starting wherever he likes and ending...

A town is laid out in a sure of side 1 kilometre, with six straight roads as shown. Each day the postman must walk the full length of every road at least once, starting wherever he likes and ending wherever he likes. How long is the shortest route he can take, in kilometres?
II (A) 4 4_ 2
(B) (C) 4 +
(D) 4 + 3Nor. (E) 5 + 2Nh.