A regression analysis between sales (Y) and advertising cost (X) resulted in the following equation: Y = 3,000 + 50 (X). The slope of the relationship means an ___________________ Question 24 options: a) increase of $1 in sales is associated with an increase of $50 in advertising cost. b) None of the options c) increase of $1 in advertising cost is associated with an increase of $50 in sales. d) increase of $1 in advertising cost is associated with an increase of $3,050 in sales. e) increase of $1 in advertising cost is associated with an increase of $3,000 in sales