The question of how long a firm will be able to sustain high growth is one of the more difficult questions to answer in a valuation. Which one of the following factors may affect the firm's high growth period length? l) Size of the firm Il) Existing growth rate Ill) Excess returns on capital IV) Magnitude and sustainability of competitive advantage a) l, Il, Ill and IV b) Il and Ill c) l, Il and Ill d)) I and Il