atherine gives piano lessons for $15 per hour. She also grows flowers, which she arranges and sells at the local farmer's market. One day she spends 5 hours planting $50 worth of seeds in her garden. Once the seeds have grown into flowers, she can sell them for $150 at the farmer's market. Katherine's accounting profits are a. $25, and her economic profits are $100. b. $75, and her economic profits are $125. c. $100, and her economic profits are $75. d. $100, and her economic profits are $25.

Google started as one of many internet search engines, amazon started as an online book seller, and ebay began as a site where people could sell used personal items in auctions. these firms have grown to be so large and dominant that they are facing antitrust scrutiny from competition regulators in the us and elsewhere. did these online giants grow by fairly beating competition, or did they use unfair advantages? are there any clouds on the horizon for these firms -- could they face diseconomies of scale or diseconomies of scope as they continue to grow? if so, what factors may limit their continued growth?