This map shows the age of the Atlantic Ocean's oceanic crust. What do the data in the map suggest?

This map shows the age of the Atlantic Ocean's oceanic crust. What do the
data in the map suggest?
ANSWER CHOICES ARE :
a. New oceanic crust is forming in the middle of the Atlantic Ocean.
b. The continental plates have stopped undergoing continental drift.
c. the sea floor is subducting under the North American plate.
d. The sea floor is shrinking along a convergent plate boundary.