US STOCKS-Wall St opens higher as oil prices continue rise
* Brent crude set for best 4-day run in a month
* Chevron up 2 pct, Exxon rises 1.5 pct
* Yum Brands slumps 18 pct on China worries
* McDonald's falls after Yum's report
* Indexes up: Dow 0.79 pct, S&P 0.69 pct, Nasdaq 0.49 pct (Updates to open)
By Abhiram Nandakumar
Oct 7 (Reuters) - Wall Street opened higher on Wednesday as crude oil prices rose for the fourth day in a row, with Brent crude on track to post its best 4-day run in more than a month.
Chevron rose 2.3 percent and Exxon rose 1.6 percent, providing the biggest boosts to the S&P 500.
The S&P energy index gained 1.9 percent, leading the advancers among the 10 major S&P sectors. Nine of the 10 sectors were up. Continuación...