How would you answer this question?

“A scientist takes a 0.5 M solution of an unknown pure dextrorotatory organic molecule and places it in a test tube with a diameter of 1 cm. He observes that a plane of polarized light is rotated 12° under these conditions. What is the specific rotation of this molecule?”

Excerpt From: Kaplan. “Kaplan MCAT Organic Chemistry Review: Created for MCAT 2015 (Kaplan Test Prep).”

Can you convert from M to g/mL without being giving additional information?

Thanks!