According to porter's five forces model, which of the following firms would be least affected by the threat of substitutes?
a) a used car dealership in new yorkb) a convenience store that sells retail productsc) a firm that sells the only drug for a diseased) corner latte shops in atlanta

Sales at a fast-food restaurant average $6,000 per day. the restaurant decided to introduce an advertising campaign to increase daily sales. to determine the effectiveness of the advertising campaign, a sample of 49 days of sales were taken. they found that the average daily sales were $6,300 per day. from past history, the restaurant knew that its population standard deviation is about $1,000. if the level of significance is 0.01, have sales increased as a result of the advertising campaign? multiple choicea)fail to reject the null hypothesis. b)reject the null hypothesis and conclude the mean is higher than $6,000 per day. c)reject the null hypothesis and conclude the mean is lower than $6,000 per day. d)reject the null hypothesis and conclude that the mean is equal to $6,000 per day. expert answer