By Stephanie Kelly NEW YORK (Reuters) – Oil prices dropped about 4% on Monday as weak manufacturing data in several countries weighed on the demand outlook while investors braced for this week’s meeting of OPEC and its producer allies on supply. Brent crude futures fell $3.94, or 3.8%, to settle at $100.03 a barrel, having fallen to a session low of $99.09 a barrel. U.S. West Texas Intermediate crude fell $4.73, or 4.8% to settle at $93.89 a barrel, after hitting a low of $92.42. A break for Brent prices below the support level of $102.68 could trigger a drop into a range of $99.52 to $101.26,…