Pass4sure 70-480 Questin Answer

You are developing a customer web form that includes the following HTML.
<input id = "txtValue" />
A customer must enter a value in the text box prior to submitting the form.
You need to add validation to the text box control.
Which HTML should you use?

A. <input id="txtValue" type="text" required="required"/>
B. <input id="txtValue" type="text" pattern="[A-Za-z]{3}" />
C. <input id="txtValue" type="required" />
D. <input id="txtValue" type="required" autocomplete="on" />

Answer: A