Which kind of sign is the car behind of?
The car is behind the stop sign.
    src        edge_attr  dst
0     1   to the left of    6
1     1  to the right of    5
2     1   to the left of   10
3     2  to the right of    6
4     3   to the left of    4
5     4  to the right of    3
6     4  to the right of    7
7     4      in front of    5
8     5   to the left of    1
9     5           behind    4
10    5            below    9
11    6   to the left of    2
12    6  to the right of    1
13    7   to the left of    4
14    8            below    9
15    9            above   10
16    9            above    4
17   10  to the right of    1