In order to make a solution more concentrated, on should (pick as many as apply)

A. add more solvent

B. add more solute

C. boil away some solvent

D. heat the solution so more solvent dissolves

E. heat the solution so more solute dissolves

B, C, E  

Explanation:

What you are trying to do is increase the solute/solvent ratio.

B. Adding more solute increases the value of the numerator, so it increases the ratio.

C. Boiling away some solvent decreases the value of the denominator, so it increases the ratio.

E. Heating the solution so more solute dissolves increases the value of the numerator, so it increases the ratio.

A is wrong. Adding more solvent makes a more dilute solution.

D is wrong. The solvent dissolves the solute.