How should you complete the relevant code?

HOTSPOT
You develop a webpage that consumes a web service. The web service provides currency
exchange rates. Visitors enter the currency type on the webpage and press the Submit
button.
The web service returns the current exchange rate.
You need to ensure that the webpage always displays the most current information.
How should you complete the relevant code? (To answer, select the appropriate option from
each drop-down list in the answer area.)

Answer:

Explanation: