The company and the effect brought about did great good to our business in the market.
A.it B.which
C.that D.what
A
【解析】
考查代词。句中的it代指the company,it brought about为定语从句,先行词the effect作brought about的宾语,故后省略了关系词which或that。句意:这家公司及其所带来的影响对我们的业务有很大的好处。故选A。