Which sentence is punctuated correctly?

A) "Are you finished yet, Miriam asked?"
B) Are you finished yet, "Miriam asked?"
C) "Are you finished yet"? Miriam asked.
D) "Are you finished yet?" Miriam asked.

Which sentence correctly uses punctuation with dialogue?

A) "Please be seated", my teacher said.
B) "Please be seated," my teacher said.
C) "Please be seated my teacher said."
D) "Please be seated my teacher said".