Qs like this are mostly intuitive and require no calculation ( of course given the choices).
Why would you invest in a bond that does not give anything for the first 4 and you hold onto it with the promise of 8% after that for the next 6 ?
Only when you don’t have better investment alternatives which puts option B and C out of contention ( the issuer will not have any taker if the 10% and 8% were avl). Hence the market interest rate must be less than 8% for the math to work. Option A becomes the choice.
But you may also be presented with all 3 options less than 8%. Then what ?
Breadmakers CF method is surest. Else you can use Magician’s trial method in TVM.
If I were there, I would observe and weigh the options first before putting my Calculator to work