Final answer:
The solution with an equilibrium constant of Ka = 1.7x10-6 is classified as a weak acid.
Step-by-step explanation:
The equilibrium constant, Ka, can be used to determine the relative strength of an acid. A larger value of Ka indicates a stronger acid, while a smaller value of Ka indicates a weaker acid. In this case, the value of Ka is 1.7x10^-6, which is a relatively small value. Therefore, the solution with this equilibrium constant is classified as a weak acid (option b).