若2a²+3a-b=4，则

=( )．

A．2

B．4

C．8

D．16

An investor has the following choices available: She can buy a 10 percent semi annual coupon, 10-year bond for $1000. She can reinvest the coupons at 12 percent. She can sell the bond in three years at an estimated price of $ 1050. Based on this information, the average annual rate of return over the three years is:

A．

B．

C．