Assertion:  One molar aqueous solution always has a higher concentration than one molal solution.

Reason:  One molar solution contains less solvent than 1 molal solution.

Both assertion and Reason are correct, and the reason is the correct explanation of the assertion.

The correct answer is option 1. Both assertion and Reason are correct, and the reason is the correct explanation of the assertion.

One molar aqueous solution is more concentrated than 1 molal aqueous solution because 1 molar solution contain 1 mole of solute in 1 litre of the solution which include both solute and solvent. So, the mass of solvent (i.e. water) is less than 1000 gram. Therefore 1 molar aqueous solution contains 1 mole of solute in less than 1000 gram of solvent whereas 1 molal solution has 1 mole of solute in 1000 gram of solvent. Hence concentration will be more in 1 molar aqueous solution.