What kind of vegetable is behind the sandwich the plate is under of?
The vegetables are olives.
    src        edge_attr  dst
0     1               on    4
1     2               on    4
2     3            under    8
3     3            below    8
4     4            above    8
5     4               on    8
6     4             with    2
7     4             with   12
8     4      in front of   13
9     4             with   13
10    4             near   13
11    4  to the right of   11
12    4            below   13
13    5  to the right of   11
14    5   to the left of    9
15    8            under    4
16    8            above    3
17    8               on    7
18    9            above   12
19    9  to the right of    5
20    9             with   13
21    9        on top of    4
22   10   to the left of   13
23   11   to the left of    4
24   11   to the left of   12
25   11   to the left of    5
26   11   to the left of   13
27   12  to the right of   11
28   12               on    4
29   12            under    9
30   12            below    9
31   13           behind    4
32   13  to the right of   11
33   13  to the right of   10
34   13               on    9
35   13            above    4
36   13               on    4
37   13             near    4