Which statement differentiates primary diamonds and alluvial diamonds?

Which statement differentiates primary diamonds and alluvial diamonds?

• A. Primary diamonds are in kimberlite pipes; alluvial diamonds are eroded and deposited in riverbeds.
• B. Alluvial diamonds are formed under pressure; primary diamonds are formed in surface sediments.
• C. Primary diamonds are synthetic; alluvial are natural.
• D. Alluvial diamonds require blasting; primary diamonds do not.

Answer: (A)