Question: To color seltzer water blue.
Options:
Open your soda bottle or can and generously stir in drops of red food coloring to create a deep, bright blue hue.
Open your soda bottle or can and generously stir in drops of blue food coloring to create a deep, bright blue hue.
Answer: Open your soda bottle or can and generously stir in drops of blue food coloring to create a deep, bright blue hue.