Write brief answers to the following question:
 
The teacher instructed three students, ‘A’, ‘B’ and ‘C’ respectively to prepare a 50% (mass by volume) solution of sodium hydroxide (NaOH). ‘A’ dissolved 50g of NaOH in 100 mL of water, ‘B’ dissolved 50g of NaOH in 100g of water, while ‘C’ dissolved 50g of NaOH in water to make 100 mL of solution. Which one of them has made the desired solution?
 
The student has made the desired solution.
Mass by volume % = x 100
Mass by volume % = 50 / 100 x 100
Mass by volume % =