A parallelogram should have 2 sets of parallel lines. Let's find the slope of line PQ and RS to test.
PQ:
(4-2)/(1-(-3))
2/4
1/2
RS:
(2-0)/(3-1)
2/2
1
Because 1 does not equal 1/2 (the slopes are different) the lines are not parallel. Thus, the figure is not a parallelogram.