Step 1: Understanding Statement I
- From B, X is 13m south-east.
- Y is 15m north of X.
- Z is 5m west of X.
We know relative positions of X, Y, Z, and B partially, but there is ambiguity because “south-east” at 13m could correspond to multiple exact coordinates without a fixed orientation grid origin.
Step 2: Understanding Statement II
- B is 6m west of X.
- Z is 8m north of X.
- Y is 12m east of Z.
Again, we have relative distances but no fixed orientation of B to Z without a definitive link to Y’s position from Statement I.
Step 3: Combining I and II
Combining still leaves ambiguity because while X’s location relative to B and Z is known, exact coordinates of B to Z direction can change if angles vary slightly — no fixed single direction emerges.
\(⇒\) Even together, not sufficient.
\[
\boxed{\text{D}}
\]