Where are Gold, Limestone and kaiolin found.

Gold is usually found embedded in quartz veins, or placer stream gravel, The most common place to find limestone is beneath the marine waters. Ocean conditions form the rock as organisms, animal skeletons, and calcium carbonate combine, Kaolinite is a layered silicate clay mineral which forms from the chemical weathering of feldspar or other aluminum silicate minerals. It is usually white, with occasionally a red color impurity due to iron oxide, or blue or brown from other minerals.

D because it is a positive that has to go back because it is being added by a negative the answer to D is 7 and 7 is to the left of 15