Read the passage and answer the questions below.

The figure below shows the street map for a certain region with the street intersections marked from a through I. A person standing at an intersection can see along straight lines to other intersections that are in her line of sight and all other people standing at these intersections. For example, a person standing at intersection g can see all people standing at intersections $\mathrm{b}, \mathrm{c}, \mathrm{e}, \mathrm{f}, \mathrm{h}$, and k . In particular, the person standing at intersection g can see the person standing at intersection e irrespective of whether there is a person standing at intersection $f$.

Six people U, V, W, X, Y, and Z, are standing at different intersections. No two people are standing at the same intersection. The following additional facts are known.

1. $\mathrm{X}, \mathrm{U}$, and Z are standing at the three corners of a triangle formed by three street segments.

2. $X$ can see only $U$ and $Z$.

3. $Y$ can see only $U$ and $W$.

4. U sees V standing in the next intersection behind Z .

5. W cannot see V or Z.

6. No one among the six is standing at intersection $d$.