There are 6 friends A, B, C, D, E and F who want to cross a bridge. However, there are two problems. First, the bridge can only accommodate two persons at a time. Second, it is night and they need the torch every time they cross the bridge (fortunately, they have one). The minimum time required by them to cross the bridge is 4 minutes, 2 minutes, 7 minutes, 11 minutes, 6 minutes and 1 minute, respectively. What is the minimum time in which they would be able to cross the bridge?
Options are - 28 29 30 31