Options:Exercise Price

Also, please explain the way we get the exercise price right for interest rate options.

Unless the questions states a specific objective (i.e. a maximum or minimum exchange rate / interest rate to aim for) then ideally you should calculate for all the exercise prices available and then discuss. However most of the marks are gained by proving that you know how options work, and so if you are short of time then just pick any one of the exercise prices available.

Any exercise price? and then state assumption right?

That is correct :-)

Thanks a ton :)

You are welcome :-)

You are welcome :-)