3. A is a common experimental method to detect protein in a biological sample. B can investigate DNA in the biological sample. Dr. Kary Banks Mullis builts a method C which can ampilify DNA in a short period of time. Based on these description, what are methods A , B and C ? (A) A: Southern blot, B: Eastern blot, C: CPR. (B) A: Southern blot, B: Western blot, C: CPR. (C) A: Western blot, B: Northern blot, C: PCR. (D) A: Western blot, B: Southern blot, C: PCR.