In box A, \$R_L\$  is in parallel with \$L\$, which has some DC resistance, \$ R_{(L)}\$.

The total resistance of \$R_L\$ and  \$ R_{(L)}\$, then, is:

$$ Rt = \frac{R_L \times R_{(L)} }{R_L \ + R_{(L)}} \text { ohms,} $$ 

which must be less than \$R_L \Omega\$ but greater than \$ 0\Omega \$. 

\$R_T\$ is in series with \$R_C\$, so their total resistance must be greater than one ohm.

Box B, however contains a one ohm resistor, so the identities of the boxes can be confirmed by measuring the end-to-end resistances of the wires protruding from the boxes.