What Allocation Unit SIze should I format my Compact Flash Card for Nickon Camera?

I have a Nikon D700 Camera…

There are several options when I FORMAT my Compact Flash Memory Card:
- Default
- 4096 bytes
- 8192 bytes
- 16 kb
- 32 kb
- 64 kb

Which one should I choose to get OPTIMUM PERFORMANCE for my D700 Camera?
are smaller or larger Allocation Units better for SPEED or safety?

Can someone explain the pros and cons of it to me?

my memory card is Compact Flash SAN DISK EXTREME, 16GB, 60MB/s UDMA

You must be formatting it in your computer. Format the memory card in your camera, it will select what the Nikon engineers have decide is best for your camera.

RetiredPhil is correct.

ALWAYS format memory cards using the format feature on the camera.

Never use the computer to format memory cards. You must use the camera's format function instead.
But, for future reference, when you format a hard drive or an solid-state-drive, you want to use small block sizes if you're saving a lot of small files such as word documents, or choose a large block size if you're saving a lot of large (e.g. Photos). When you save a file to a block or set of blocks, all of the space within those blocks are reserved for that specific file. So if you choose a large block of lets say 4,096 bytes, when you save a 5,200 byte file, the computer will have to reserve two 4,096 blocks. So you end up using 8,112 bytes to save a 5,200 byte file. Not very efficient, is it?
On the other hand, choosing a small 64kb block size when saving large files, means that the computer will take longer to write the file because it using too many blocks. Remember, the blocks are not necessarily continuous. You could be using 64kb here and 64kb there, which requires the HDD drive to move the read/write head to numerous locations. This is why you want to defrag your hard drive on a regular basis. However, you don't need to defrag an SSD.