You are an independent consultant selling an ebook you wrote about Search Engine Marketing for $50. You have campaigns across multiple online advertising platforms: search networks, display networks, & other advertising networks. Which approach to CPA targets and budget is best suited to maximize your total profit?
A) Predetermined budget to be divided across all platforms. Allocate the most budget to the platforms with the lowest CPA
B) Unlimited budget on all platforms where ROI is positive. Use a single CPA taret for all channels which matches the channel with the lowest CPA
C) Predetermined budget, to be divided equally across all platforms. Minimize CPA on all platforms
D) Unlimited budget on all platforms where ROI is positive. Find a different CPA for each platform which maximizes profit based on costs, sales volume, & contribution to overall marketing campaign