0.500 M KCl = 37.27 g/L
0.500 wt % KCl = 5 g /L
1.75 M glucose = 315.28 g/L
1.75 molal glucose means 315.28 g/L
A molar solution is where 1mol of solute is dissolved in 1 litre of final solution. Because the solute must contribute some volume to the final solution to get a 1molar solution you will require less than 1000 ml or 1000 grams of water.
A molal solution is one where 1mol of the solute is dissolved in 1000g ( or, in the case of water, 1000ml) of the solvent. The volume of the solution will be greater than 1 litre.
Because in the case of the molar solution, the solute is dissolved in less water than in the molal solution, molar solution will have a higher concentration.
So, from the above discussion, 0.500 M KCl is more conc. than 0.500 wt % KCl.
Between 1.75 M glucose and 1.75 molal glucose, 1.75 molar glucose is more concentrated.
The correct option is (a).