The term "content adjacency" refers to:

a$.$

a concern that an advertisement will run near offensive material, embarrassing an advertiser and$/$or degrading their products or brands

b$.$

placing advertisements to reach consumers based on various traits such as demographics and purchase history

c$.$

a technique used by online publishers to increase the effectiveness of their campaigns

d$.$

advertisements that are targeted based on a user's query

e$.$

problems associated with advertisements that run before a user arrives at the home page of a website