non-callable bond

In one section it says option free bonds are not dependent on interest rates but when doing a practice test it says the non-callable bond is affected by changing interest rates? So which is it?

I have no idea why they they’d say that option-free bonds are not dependent on interest rates. Any bond whose (modified) duration isn’t zero depends on interest rates: their value changes as their YTM changes.

It would be nice to see that quote in context.