Copper prices are down twenty percent over the past three months.

On Wednesday, September High Grade Copper futures lost 1.5 percent to end at $2.27 per pound on the Comex division of the New York Mercantile Exchange,

This is the lowest level for the metal since the financial crisis six years ago

Alan Knuckman, chief options strategist at Bulls-Eye Options told CNBC's "Power Lunch" the dollar's rise is to blame for the copper crush.

"The greenback is still king, and that rules everything," said Knuckman. "If you are trying to pick a bottom in copper, and in fact, all commodities, you have to pick a top in the dollar. Which, by the way, is pretty much impossible."

So how do you play the metal?

Knuckman recommends buying long-term options on Freeport McMoRan, a natural resources company with headquarters in Phoenix, Arizona and world's largest publically traded copper producer.

"The stock set a new 52 week low of $9.59 today, down 75 percent in the last year," said Knuckman. "So from a risk-reward standpoint, it's a good buy value at prices not seen since the financial crisis."

In the first half of 2015, the copper miner produced nearly two billion pounds of copper, which it sold at an average $2.70 per pound.