Hi I need help for this question. Thanks
What part of this do you need help on? There are a lot of concepts here.
Both interest rate cap and european put option will meet her needs. They both increase in value when rates rise, thus, protects against interst risk. And she can keep the capital appreciation should rates decline.
European put on interest rate will not work, it does not protect against interst rate rise.
Not sure about B but I believe there is no advantage for early exercise of a put option on a bond forward contract because the underlying bond forward will not give you any interest payment anyways.