When setting up a campaign, you can use Display Planner to get an idea of the budget and bids you should set based on your

• traffic estimates for placement ideas
• historical conversion rate estimates for your keyword and placement ideas
• historical cost-per-click (CPC) estimates for your keyword and placement ideas
• traffic estimates for your keyword ideas

Correct answer is:

• historical cost-per-click (CPC) estimates for your keyword and placement ideas

Explanation: Each idea comes with impression estimates and historical costs. Think of these estimates and statistics as a guide to help you plan your Display Network campaign, rather than to project future performance.

Read more here: https://support.google.com/adwords/answer/3056153?hl=en