Answer from cs61c-ax (Amanda Alfonso 15906918) for Question 2
Statements B and D are true.  B is true because a newly freed block may be adjacent to another free block, in which case the two blocks are combined and there is no net change in the number of free blocks.  Similarly, if a newly freed block fits exactly between two adjacent blocks, then all three are combined, resulting in a net decrease of 2 in the total number of free blocks.