By Combining Lending and Borrowing at the Risk-Free Rate with Efficient

By combining lending and borrowing at the risk-free rate with efficient portfolios,we can:
I.extend the range of investment possibilities;
II.change the set of efficient portfolios from being curvilinear to a straight line;
III.provide a higher expected return for any level of risk,except for the tangential portfolio and the risk-free asset

A) I only
B) I and II only
C) I,II,and III
D) II and III only