A Luminol Solution Is Used to Detect the Presence of Blood

A luminol solution is used to detect the presence of blood. What is the molarity of a luminol solution that was made by dissolving 15.5 g of luminol (C₈H₇N₃O₂) in water to a final volume of 90.0 mL?

A) 0.0875 M
B) 0.972 M
C) 0.172 M
D) 0.00787 M