Every product has a life cycle. The four life cycle stages are: introduction, _______, maturity and decline. A: prodution B: development C: modification D: growth

Before setting up the business, they conducted a market survey about prodution, sales and after-sales service. A: 如果要创业，他们得有一笔启动资金，并且要有销售渠道。 B: 在创业前，他们对生产、销售和售后服务进行了市场调研。 C: 在开展业务之前，他们对该产品的售后服务进行了市场调查。