Suppose following is the given table Graph:

1. $ π._{Y}(\sigma_X='vertex-number'(GRAPH))$ // vertex adjacent to a given vertex
2. $ π._{Y}(\sigma_X=y(GRAPH))$ //vertices with self loop
3. If we look into the table, $1->2, 2->1$, it's a cycle of length 2, which contains vertices less than $3 (<=2)$, it also needs a constant length RA query, which is quite complex to be written, but we can take the cross product between the two instances of the same table and can find it.
4. not possible with constant length query, for example $1->2, 2->3, 3->4$, and so on.. 2,3,4 and so on are reachable from vertex 1, and this list can go further.
Hence (D) is the correct option!