I will say 3 is wrong because the time of day doesn't matter.But what really matters is 1,2,4 we just need to figure which one is correct.
1.The Wife's blood
Real blood will smell bad and with the time it will turn the color red to a dark-ish color red with brown.To see if it is real you have to see if the blood is a dark brown with red if it's not then it's a fake.
2.The type of Gun
You have to feel if it's a fake it might be plastic or another toy material.The gun has to feel like metal.
So the answer might be 1 or 2
Hope this helps :)