ETNs (Exchange Traded Notes) are considered as what type of investment dropdown in the Sales Info section?

The dropdown options are:
-Stock
-Mutual fund, Index Fund, or ETF
-Bond
-Options
-Land
-Collectible
-Personal Items
-Other

**It's either Index Fund or Other, just not clear on which one. The ETN in question is "JO" the coffee ETN that tracks the commodity index fund, but is not an index fund itself. Should I use Other?