Which of the following solutions has a 1.0 M?

A. 0.050 mol of solute in 25.0 ml solution

B. 2.0 mol of solute in 500.0 ml of solution

C. both answers are correct

D. there is not correct answer

Molarity=mols/L as such we have the following:

0.05 mol / 0.025 L = 20 M

2.0 mol / 0.5 L = 4 M

Based on these calculations we can say that D is the correct answer since neither A or B are the answer which also eliminates option C.