FRM一级模拟自测:An investment advisor is advising

An investment advisor is advising a wealthy client of the company. The client would like to invest USD 500,000 in a bond rated at least AA. The advisor is considering bonds issued by Company X, Company Y, and Company Z, and wants to choose a bond that satisfies the client’s rating requirement, but also has the highest yield to maturity. The advisor has gathered the following information:
  X Y Z
Bond Rating AA+ A+ AAA
Semiannual Coupon 1.75% 1.78% 1.69%
Term to Maturity in years 5 5 5
Price (USD) 975 973 989
Par value (USD) 1000 1000 1000
Which bond should the investment advisor purchase for the client?
a. Y bond
b. X bond
c. Z bond
d. Either the Z bond or the Y bond