Which sentence contains an error in the use of end marks or commas?

A.
Dr. and Mrs. Majeck will attend the party on March 12, 2014.

B.
Address inquires to Ella Adams, 315 Elm St, St. Petersburg, FL 33707.

C.
Miss K.C. Fairchild will lead the band in a Sousa march.

D.
Mom, what does B.C. mean?