Consider a 2-year zero-coupon bond issued by Dog Grooming Inc. The par value is $1000. Suppose the bond is not risk-free, in the sense that bond holders will only receive 50% of the principal back at the end of year 2 if default happens. Assume the default probability is equal to 0.5; the annual risk-free rate is 4%; and the current bond price is $600. a. Please compute the promised yield-to-maturity, the expected yield-to-maturity, the default premium and the risk premium