Which of the following is a property of sodium salt? 

Alkali metal salts often produce their distinctive hues when burnt with Bunsen flame. It is used to determine if the given substance contains alkali metal salts. It's known as a flame test.

What is the attribute of the sodium salt among the possibilities mentioned in the question?
There will be a production of various colours depending on the specific alkali metal salt when we burn the alkali metal salts in Bunsen flame.
Regarding lithium salt, a flame test reveals that it is red in colour.
In flame tests, potassium salts produce a violet tint.
Sodium salts when burnt in a flame produce a yellow-orange hue.
Because of this, the sodium salts will generate a yellow-orange hue during the flame test.

Hence option (D) is correct.