Answer from cs61c-ad (Maung Maung Aung 16764789) for Question 2
a) False. A call to free may combine the adjacent blocks with the block being free. So, the number of free blocks may decrease.

b) True. Like I mentioned in 'a' it might happen.

c) False. There are chances that the block being free lies between two free blocks. Then after they combine, there may be more than 1 number of blocks will decrease.

d) False. The maximum number of blocks which can reduce is 2. No more than 2.