You Have a Patient Who Needs a Lot of Blood

You have a patient who needs a lot of blood.The patient is blood type A+.You have the following blood in stock.How many liters of blood can you give the patient before you will have to find other sources of blood?
Blood type
Liters available
O+
2
O-
12
A+
4
A-
4
B+
10
B-
24
AB+
30

A) 8
B) 14
C) 22
D) 46
E) 86