Based on concentration of solute particles and hence the osmotic pressure the solutions can be classified into three categories , with respect to other solutions
a) isotonic: when concentration of one of the solution is same as of the other solution then they are referred as isotonic to each other.
b) hypertonic: When concentration of the solution is greater than the concentration of other solution then it is said to be hypertonic.
c) hypotonic: when concentration of the solution is lesser than the concentration of other solution then it is said to be hypotonic.
So a solution with high concentration of solute will have higher osomotic pressure and will called to have high pressure or tone hence called as hypertonic.
Thus compartment A will have high concentration and will called as hypertonic while the compartment B will have low concentration and will called as hypotonic