Barium hydroxide is a sparingly soluble salt.

Could someone please show me how to answer this question:

Barium hydroxide is a sparingly soluble salt. A solution was prepared in a flask with a slight excess of barium hydroxide so that some remained undissolved. The system is represented by the equilibrium:

Ba(OH)2(s) <-----------> Ba2+(aq) + 2OH-(aq)

A few drops of 5M hydrochloric acid were added to the flask. After this addition, which of the following would best describe the system?

A. No change is observed

B. The pH of the solution increases

C. More Ba(OH)2(s) is precipitated

D. Some of the Ba(OH)2(s) dissolves