The Best ETF/Option Product to Short Crude Oil?

As the title says. I'm an options trader and don't have approval or the risk appetite to trade oil futures directly.

As someone outside of the commodities trading game, what is the most efficient method for shorting oil over a time period of say six months from now? I'm guessing that options on oil futures might be possible?

Preferably I'd like to do it with an option spread rather than just buying an inverse ETF.

Thanks.