问题如下：
Which of the following trading instruments would have the most beneficial effect on netting?
选项： A. Options with up-front premiums.
B. Equity options.
C. FX options.
D. Futures.
解释：
D A trading instrument will have a beneficial effect on netting if it can have a negative mark-to-market (MtM) value during its life. For instruments whose MtM value can only be positive during their life, the effect on netting will not be as beneficial. Instruments with only positive MtM values include options with up-front premiums such as equity options, as well as swaptions, caps and floors, and FX options. Futures can have negative MtM values.
理解netting效果好的时候是其exposure有正有负的时候，所以选择futrue，但是对option的话，long option的头寸一定是正的，netting效果可能不好，但是short option的头寸不是也有正有负吗？还是说short option的收益有限，所以做netting效果不如futrue？
