Please help i only got 2 weeks to do

Maria wants to determine which type of disinfectant kills the most bacteria. which of the following is the best way for maria to determine this? a. ask ten different companies that make disinfectants which type is best. b. put the same amount and species of bacteria on ten identical plates, and add ten different kinds of disinfectant to each plate. c. interview ten different people to determine which type of disinfectant they prefer. d. put the same amount and species of bacteria on ten identical plates, and add a different disinfectant to each plate.

How much would the freezing point of water decrease if 4 mol of sugar were added to 1 kg of water(k=1.86 c/mol/kg for water and i=1 for sugar

What effect might melting sea ice have for people who live in coastal areas?