What Is the Challenge Presented to Brand Managers by Social

What is the challenge presented to brand managers by social media advertising?

A) Brand managers need to realize that social media are less likely to have a marketing objective of immediate sales than traditional media.
B) Brand managers need to convince social networks to post their ads free of charge.
C) Brand managers need to create "universally appealing" ads since they cannot target specific demographics on social networks.
D) Brand managers have difficulty estimating how many users have clicked on their ads,which leads to problems in assessing an ad's effectiveness.
E) Brand managers need to realize that there are only a few social networks to advertise on.