Answer:
D. Words in your ad text, like model names of digital cameras
Step-by-step explanation:
The key words are important for SEO purposes; these connect the search engines systems with the ad done through the clients research about specific words.
Having these options you will introduce words of the ad text taking on account that it is the way that people will identify your ad and find it through search engines. When you add something like model names of digital cameras there are more chances to guide a specific to your virtual ad