Which of the following classes is used to enable sections of a page to be partially rendered without a
postback?

A.
UpdateProgress

B.
ScriptManager

C.
Timer

D.
UpdatePanel

Explanation:
The UpdatePanel control is a server control that enables a user to define areas of a page that should
postback to the server without refreshing the whole page. This is known as partial-page update. This
process is organized by the ScriptManager server control and the client PageRequestManager class.
The partial-page updates are enabled by default, as the default value of the EnablePartialRendering

property of the ScriptManager control is true. The controls postback to the server asynchronously
when the partial-page updates are enabled.
Answer B is incorrect. The ScriptManager control is used to enable AJAX functionality in ASP.NET. It
handles all ASP.NET AJAX resources on a page. This includes downloading Microsoft AJAX Library
scripts to the browser and managing partial-page updates enabled by using UpdatePanel. By default,
ScriptManager is used to register the script for the Microsoft AJAX Library with the page.
Answer A is incorrect. The UpdateProgress control is used to provide status information of a partialpage update in the form of graphics or text. Multiple UpdateProgress controls can be used in a page
where each control is associated with a different UpdatePanel control or a single UpdateProgess
control can be associated with all UpdatePanel controls on the page.
Answer C is incorrect. The ASP.NET Timer control is an AJAX control that updates a portion of a page
on a periodic basis. It performs asynchronous or synchronous postback of a page at a defined time
period. The interval property of the Timer control specifies the number of milliseconds to wait
before initiating a postback.