Answer: Option 'd' is correct
Step-by-step explanation:
The process by which lithospheric plates move apart creating spaces that are filled with hot magma is called "Seafloor Spreading".
Sea floor happened at divergent plated boundaries ( i.e. in the different directions) so, the plates would move apart due to which it creates spaces that is filled with hot magma.
Then, it forms the new crust.
Divergent boundaries results in spreading the ocean.
Hence, Option 'd' is correct.