Statements I and III are accurate.

Statement I is correct as it accurately describes the concept of zero rates. In the context of bonds, a zero rate is the discount rate that is used for discounting a single cash flow at a specific future time or maturity. This rate corresponds to the yield of a zero-coupon bond, which is a bond that does not pay interest but is sold at a deep discount. This discount compensates for the lack of interest payments. When the bond matures, the bondholder is paid the face value of the bond. The yield, or the rate of return, of a zero-coupon bond is the rate that makes the present value of the bond's future cash flows equal to its current market price.

Statement III is also correct as it accurately describes the concept of par yield. The par yield is the coupon rate of a bond that, if applied, makes the bond price equal to its par value. The par value of a bond is its face value, or the amount that the issuer promises to pay the bondholder when the bond matures. The par yield is the coupon rate that makes the present value of the bond's future cash flows, including both the periodic coupon payments and the face value payment at maturity, equal to the bond's par value.

Therefore, both statements I and III accurately describe key concepts related to bonds and their associated rates.

Choice A is incorrect. While Statement I is correct, Statement II is not. The yield of a bond, also known as the yield to maturity (YTM), is indeed the discount rate that equates the present value of a bond's future cash flows to its market price. However, it should not be confused with the spot rate which refers to the theoretical yield of a zero-coupon Treasury security.

Choice B is incorrect. As explained above, Statement II is inaccurate because it incorrectly equates a bond's yield or YTM with the spot rate. Although Statement III correctly defines par yield as being the coupon rate that makes a bond's price equal to its par value, this choice cannot be correct due to the inaccuracy in Statement II.