A market maker holds an inventory of shares in order to provide immediate liquidity to traders in a particular stock market. The market maker is compensated by the bid-ask spread. Which of the following will likely increase the bidask spread? I. Unusually high trading activity in a particular stock II. Multiple market makers competing for order flow III. Market-wide volatility IV. Many of the stock in the inventory have an increase in the debt-to-equity ratio. I only II only III only IV only I and II I and III II and IV