The correct answer is (B) Adding a dilute solution of HCl
EXPLANATION
The presence of carbonate ions can be tested by adding a dilute acid to the solution. The acid displaces Carbon (IV) oxide from the solution. Using HCl, and a carbonate of metal X.
XCOââsâ + 2HClâaqââ XClââaqâ+ HâOâlâ + COââgâ
The gas produced is tested using calcium hydroxide to confirm whether it is carbon (IV) oxide.