To use language vividly, your textbook recommends that speakers employ:

Imagery and rhythm are two good techniques that can be employed when trying to engage one's listeners. This way, the speaker can have a topic that becomes more interesting and "paints a picture" in the mind of the listeners, giving them a more accurate sense of the topic that the speaker is trying to deliver.

It's most likely choice a, it makes the most sense in my opinion.

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.