The average density of blood is 1.06 × 103 kg/m3. if you donate a pint of blood to the red cross, what mass of blood have you donated, in grams? (1 pt = 1/2 l, 1 l = 1000 cm3.)

265grams

To answer this question you need to know how much the blood volume in m3. The amount of blood will be: 1/2pt x 1/2 l/pt= 1/4 litre. If you convert the litre to m3 then you will get 1/4 x 10^-3 m3.
The mass of blood would be 1.06 × 10^3 kg/m3 x 1/4 x 10^-3 m3= 1.06 x 1/4 kg= 0.265kg. Last, convert it into grams: 0.265kg x 1000grams/kg= 265grams

Ithink d is the right answer. hope this !