A Retailer, in Business for Over 50 Years, Has Developed

Multiple Choice

A retailer, in business for over 50 years, has developed the following regression model from the past 60 months of operating data:
Monthly sales dollars = $50,000 + $4.70A + $30B − $1,000X
Where:
A = number of customers
B = advertising dollars per month
X = 1 if a winter month
X = 0 if other months
An appropriate interpretation of this model is that:

A) The business is seasonal, generating higher sales in winter months than other months.
B) Advertising is not cost effective.
C) Within the relevant range, each additional customer will make an average purchase of $4.70 per month.
D) Sales are always expected to be at least $50,000.