An aqueous solution with density 0.988 g/mL at 20 °C is prepared by dissolving 12.8 mL CH₃CH₂CH₂OH (d = 0.803 g/mL) in enough water to produce 75.0 mL of solution. What is the percent CH₃CH₂CH₂OH expressed as 

(a) Percent by volume; 

(b) Percent by mass; 

(c) Percent (mass/volume)?