Answer and explanation:
Stellar is a Brazilian cryptocurrency that is used to facilitate low cost and flexible payment. It was renamed lumens and is denoted XLM.
One stellar lumen is currently equal to $0.219096
For the purpose of the question and since it does not specify exchange rates for each bank, let's assume:
Bank A= 0.219097 to 1 US dollar
Bank B= 0.219099 to 1 US dollar
Using Bank A to exchange $1700 for stellars= $1700*0.219097= 372.464 stellars
Using Bank B to exchange $1700 for stellars= $1700*0.229042= 389.3714 stellars
From the above, we can see that Bank B has a better exchange rate as it is cheaper than Bank A(gives more stellar) . She should therefore use Bank B for her exchange.