The best answer is d - Water.
Plasma is a water solution that is pale yellow in color in which all other parts of the blood are suspended.
Plasma is made up of approximately 92 % water. Proteins, enzymes, glucose, amino acids, minerals, urea, vitamins, uric acid, antibodies, salts and hormones make up the remaining 8% .
Whole blood is composed of 55% plasma. Plasma in blood acts as a solvent for gases, electrolytes, nutrients and important proteins vital to life.