Hello~
millibar - a unit of atmospheric pressure equal to one thousandth of a bar; "atmospheric pressure at sea level is 1013 millibars" pressure unit - a unit measuring force per unit area bar - (meteorology) a unit of pressure equal to a million dynes per square centimeter; "unfortunately some writers have used bar for one dyne per square centimeter"
So the answer is D. 1013mb
Ary~