I have problems with this question. Can anybody help me?

Question

When dilute nitric acid was added to a solution of one of the following chemicals, a gas was evolved. This gas turned a drop of limewater. Ca(OH)2, cloudy,due to the formation of a white precipitate. The chemical was...

A. NH3
B. NaHCO3
C. NaCl
D. MgSO4x7H20
E. 5% NaOCl

Answer 1

The classic test for carbon dioxide (CO2) is the lime water test.
Ca(OH)2 + CO2 ==> CaCO3(white solid) + H2O
Which of the five do you think will evolve CO2 gas?