I need answer for (b), thank you!

a. iShares Russell 2000 is a growth ETF by BlackRock with an inception date of July 24, 2000. When it first got introduced into market it was priced at $76.31/share. Currently it is trading at $211.62 per share. What is the current premium as a percentage of its original NAV? (0.5 pt.) b. Suppose that the ETF's price falls below its net asset value. Describe what authorized participants (APs) could do to take advantage of this discrepancy. What would be the likely effect of the APs' actions? (1 pt.)