Allocating memory via Buddy Allocation
None of the above.  First, block sizes are rounded up to the nearest power of 2.  If you try to allocate an object of length 5K, it will first round that up to 8K.  Next, it will try to find a free block of size 8K.  In your example, you'll need to look at larger blocks -- the 1K, 2K, and 4K blocks are too small.  You'd better hope there is another 8K block (not shown) that is free, or an even larger block that is free and can be split up to create a 8K block.