US STOCKS-Plunging oil prices drag down Wall Street
* Brent crude near 7-year lows after OPEC's meeting last week
* Atlanta Fed's Lockhart says market prepared for a hike - CNBC
* Keurig soars on $13.9 bln buyout offer
* Chipotle falls after sales warning
* Indexes down: Dow 0.33 pct, S&P 0.38 pct, Nasdaq 0.16 pct (Updates to open)
By Tanya Agrawal
Dec 7 (Reuters) - Wall Street was lower at the open on Monday as Brent crude prices fell to their lowest in nearly seven years after OPEC's meeting ended last week without a reference to its output ceiling.
Brent crude prices fell to $38.80, while a stronger dollar made it more expensive to hold crude positions. The dollar rose for a second day and was up 0.5 percent at 98.84 against a basket of major currencies.
Oil majors Exxon and Chevron fell about 3 percent and were the biggest drags on the Dow and the S&P. Continuación...