Which of the following is not the evidence of the occurrence of seafloor spreading?

A. Normal and reversed polarity/magnetic stripes alternated across the ocean's bottom

B. The upward movement of molten magma due to convection currents in the mantle causes the rocks at/near the mid-ocean ridge to become warmer

C. Older rocks were discovered at the center of a mid-ocean ridge, while younger rocks were found away/far from the mid-ocean ridge

D. The difference in the age of rocks collected away from and at the center of a mid-ocean ridge through seafloor drilling​