Two objects are in contact. which of the following conditions will yield the greatest rate of heat flow between the objects?

a. object a is at -20, and object b is at 20 degrees c

b. object a is at -20 degrees c, and object b is at 0 degrees c

c. object a is at 0 degrees c, and object b is at 0 degrees c

d. object a is at -10 degrees c, and object b is at 10 degrees c