Albumin Is a Protein in the Plasma Portion of the Blood

Albumin is a protein in the plasma portion of the blood. Under normal conditions albumin cannot pass through the wall of a capillary. What significance is this for the vascular compartment?

A) Helps push oxygen into the tissues of the body.
B) Retains leukocytes in the vascular compartment.
C) Helps retain fluid in the vascular compartment.
D) Absorbs carbon dioxide from the tissues for transport to the lungs.