Bentonite clay, which consists of ancient volcanic ash, has many uses, including manufacturing kitty litter and clarifying wine. A major use is for drilling mud, a material pumped down oil and gas wells during drilling to keep the drilling bit cool. When oil drilling decreases, less bentonite is demanded at any given price. The price of crude oil was about $50 a barrel in 2016–2017. However, by 2018, it was over $70, causing drilling to increase. Use a supply-anddemand diagram to show the effect on the bentonite market and explain in words what happened.