A common practice is to create a(n) on any field that is used as a search key, in comparison operations in a conditional expression, or when a user wants to list rows in a specific order.

Lucas put a lot of thought into the design for his company's new white paper. he made sure to include repeating design elements such as color schemes and decorative images. his goal was to a.add symmetry b.create a unified publication c.provide consistency d.save money