Nhat did the Curies conclude about radioactivity based on their studies? A-The amount of radioactivity is an extensive property because it varies as the amount of material varies.

B-The amount of radioactivity is an extensive property because it remains constant as the amount of material varies.

C-The amount of radioactivity is an intensive property because it varies as the amount of material varies

D-The amount of radioactivity is an intensive property because it remains constant as the amount of material varies.