Which of the Following Factors Will Cause Analysis of Blood

Which of the following factors will cause analysis of blood gas samples to be erroneous?
1) Warming the sample
2) Low leukocyte counts
3) The presence of air bubbles in the sample
4) Icing the sample between obtaining and analyzing
5) Prolonged time delay between obtaining and analyzing a sample

A) 2 and 3
B) 2 and 4
C) 1,3,and 5
D) 1,2,4,and 5