Which option should you choose to find out how many questions a client has answered?

Choosing to hover over the progress icon is the optimal way to determine how many questions a client has answered. This action typically brings up a tooltip or additional information that displays detailed statistics about the client's responses, including the number of questions they have engaged with. This method is efficient and allows for immediate feedback without needing to navigate away from the current interface or disturb the client.

In contrast, contacting the client could provide you with the information, but it’s less efficient as it involves waiting for a response. Opening the query might lead to more information related to specific questions but doesn’t directly provide a summary of the total answered questions. Checking the client list may present some basic statistics, but it usually lacks the detailed breakdown of answered questions that hovering over the progress icon can offer. Thus, hovering over the progress icon is the most direct and effective method to gain insights into the client's engagement with the questions.