Answer:
fast responses at a lower cost
Explanation:
Based on the information provided it can be said that Charles will likely use an online survey primarily because it offers fast responses at a lower cost. This is because the customers receive this in their mail and/or e-mail, and are easily able to fill it out in a couple of minutes. If Charles send's the survey through mail it will be one of the cheapest options other than e-mail which is completely free.
