Can you me with these three questions?

4.92  = 1 x 4 + 9 x 10 + 2 x 100 

21.8 = 1 x 21 + 8 x 10 

31.064 = 1 x 31 + 0 x 10 + 6 x 100 + 4 x 1000

There is no reason to think the results are biased or not conducted properly but you should not assume the results are correct just because they were done in a laboratory so the answer would be c. it is likely to be reliable because the results support the conclusion presented.

Molarity is moles of solute over liters of solution. idk if that is what you are talking about, but you can convert moles of solute to grams of solute using dimensional analyzes by using molar mass found on the periodic table.