Which word has a strongest positive connotation to replace the word valued a. favored b. treasured c. admired d. appreciated

Treasured.
Favored means there are other candidates and the choice is very close of what to pick.

Admired is just looking up to someone. Valued is a much stronger word than admired. Valued implies that there is something worth having. Treasured is above that. So admired doesn't figure.

Appreciated is also a weak word compared to valued. 

B. <<<< answer.

Currently, as of february 2016, an american traveling in france would be by the exchange rate. the weakness of the euro and the strength of the us dollar means that items in france cost less to an american than they otherwise would. of course, if this trend reverses and the us dollar weakens and the euro strengthens, such as was happening in early 2008, an american traveling in france would have an adverse experience because items would cost relatively more.