What XSL component is required to execute valid transformation instructions in the XSLT code?

The is the core component in XSLT. It defines the transformation rules that will be applied to nodes in the XML document.

“Without at least one element, an XSLT file cannot perform any transformation. This is the execution block where processing logic begins.”

Why the others are incorrect:

B. applies templates but is not valid without the actual template definitions.

C. calls named templates — which must first exist.

D. defines format but does not perform transformation logic.