Differential centrifugation divides cellular components based on the differences in their size and / or density. A tissue sample was homogenized and three parts (aliquots) of this homogenate were subjected to differential centrifugation using three dissimilar methods as shown below:

Method I: Aliquot 1 was centrifuged at 200,000g for 2 h.

Method II: Aliquot 2 was centrifuged at dissimilar speeds and for variable durations as shown below:

Step 1: 1,000g for 10 min

Step 2: 20,000g for 20 min

Step 3: 80,000g for 1 h

Step 4: 200,000g for 2 h

Method III: Aliquot 3 was processed in the same manner as aliquot 2, except that the sediment and supernatant were divided after each step.

 Cellular components can be obtained as separate fractions from which of these methods?

a.  Only method I 

b.  Only method II

c.  Only method III 

d.  Both methods II and III