To answer this question, you need to understand the structure of the taglib descriptor file (TLD) and which elements are required.
Let's go through each option to understand why it is correct or incorrect:
Option A) name - This option is correct because the "name" attribute is required in the taglib element. It specifies the unique name for the tag library.
Option B) description - This option is incorrect because the "description" element is optional. It provides a description or documentation for the tag library, but it is not required.
Option C) validator - This option is incorrect because the "validator" element is optional. It is used to define a validator class for the tag library, but it is not required.
Option D) tag-class - This option is correct because the "tag-class" element is required in the taglib element. It specifies the fully qualified class name of the tag handler class.
Option E) display-name - This option is incorrect because the "display-name" element is optional. It is used to provide a human-readable name for the tag library, but it is not required.
Therefore, the correct answers are A) name and D) tag-class. These elements are required in the taglib element of the taglib descriptor file.