A possible relational algebra query for option C :
$\pi _{\text{ u1, v1}} [ \sigma _{\text{ (v1 = u2 AND v2 = u1) OR (u1 = v1 AND u2 = u1 AND u2 = v2) }} ( \xi _{\text{ u1, v1}} Adj \times \xi _{\text{ u2, v2}} Adj ) ]$
Cycles of with atmost two vertices.