Answer
a. $HC_2H_3O_2$ will produce a solution that contains mostly molecules and a few ions.
b. $NaBr$ will produce a solution that contains only ions.
c. $C_6H_{12}O_6$ will produce a solution that contains only molecules.
Work Step by Step
According to the table 9.4 (page 330):
Strong electrolytes produce solutions that contains ions only.
Weak electrolytes produce solutions that contains mostly molecules and a few ions.
Nonelectrolytes produce solutions that contain molecules only.