Answer:
About 75 percent of liquid antibacterial soaps and 30 percent of bars use a chemical called triclosan as an active ingredient. The drug, which was originally used strictly in hospital settings, was adopted by manufacturers of soaps and other home products during the 1990s, eventually ballooning into an industry that's worth an estimated $1 billion. Apart from soap, we've begun putting the chemical in wipes, hand gels, cutting boards, mattress pads and all sorts of home items as we try our best to eradicate any trace of bacteria from our environment.
The answer is D. Because the other answer have dependent marker words such as Do and After.
A cause-and-effect relationship is signaled by the words "But since."