Assertion: 1 molar solution is more concentrated than 1 molal solution.
Reason: A molar solution contains 1 mole of solute in 1000 mL of solution.
a) A and R are true, R is correct explanation of A
b) A and R are true, R is not correct explanation of A
c) A is true, R is false
d) A is false, R is true
This topic was explained here.
https://www.chemtopper.com/smf/cbse-xi-and-xii-chemistry/resume-graduate-school-skills/
Depending of the density rho < 1 d could be the right answer or none of them.
c = n/V, Rho = m/V
1 molar solution is more concentrated than 1 molal and this can be explained using density concept. Assertion can be true but reason is not the correct explanation of the assertion.
A molar solution contains 1 mole of solute in 1000 mL of solution and this is also correct statement.