At the time that an article was first featured on the home page of a news website, there were $40$ comments on the article. An exponential model estimates that at the end of each hour after the article was first featured on the home page, the number of comments on the article had increased by $190\%$ of the number of comments on the article at the end of the previous hour. Which of the following equations best represents this model, where $C$ is the estimated number of comments on the article $t$ hours after the article was first featured on the home page and $t\le 4$?