Question

Which of the following is not a diameter?

SV
RU 
WT

Answer 1

WT
It does not perfectly cut the circle in half.

Answer 2

The center of the circle is point A
the diameter would be a line with 2 points that cross through point A

the line with points WT cross through pint which is not at the center (Point A)
so WT would not be a diameter.