A graduate student working on her Ph.D. dissertation observes a Cepheid variable star in the Large Magellanic Cloud. The star has a mean magnitude of m = +15.56 and a period of 4.76 days. Using the Cepheid period-luminosity relationship, What is the mean absolute magnitude, M, of the star?
1) -5.10
2) -3.10
3) -1.10
4) 3.10
5) 5.10
