CSS stands for:

 a) Comprehensive Style Sheets
 b) Collecting Style sheets
 c) Comparative style sheets
 d) Cascading Style sheets

KWA-2015

Cascading Style sheets. Cascading Style Sheets (CSS) is a) is a style sheet language used for describing the look and formatting of a document written in a markup language.(e.g., fonts, colors, spacing) to Web documents.