Futures price vs. CTD bond price

CFA Level III
#1

When modifying portfolio duration with futures, some questions appear to provide futures prices, some CTD bond prices, and some provide both.

It appears that when they provide both they want you to use the CTD bond price, but I am just doing another question now where only the futures price is provided. Does anyone know when to use what?

Thanks

#2

With Practice you would know… You can easily figure it out if you know the concept well

#3

Look at the duration they provide. Do they provide it for the CTD or the futures…?!