Apurely competitive firm can be identified by the fact that a. there are other firms in the industry producing similar productsb. it is making only normal profits in the short runc. its average revenue equals its marginal revenued. it experiences diminishing marginal returns

Leading guitar string producer wound up inc. has enjoyed a competitive advantage based on its proprietary coating that gives its strings a clearer sound and longer lifespan than uncoated strings. one of wound up's competitors, however, has recently developed a similar coating using less expensive ingredients, which allows it to charge a lower price than wound up for similar-quality strings. wound up's competitive advantage is in danger due to a. a lack of perceived value b. a lack of organization c. direct imitation and substitution d. resource immobility