Here's a question from an actuarial CAS Exam 2. Can someone show me how to do it. I know the answer is (A), but I'm not sure why.

A 30-year bond has 10% annual coupons and a par value of 1000. Coupons can be reinvested at a nominal annual rate of 6% convertible semi-annually. X is the highest price that an investor can pay for the bond and obtain an effective yield of at least 10%

Calculate X.

(A) 518

(B) 618

(C) 718

(D) 818

(E) 918

Thanks in advance for your help.