Linking a YouTube channel to a Google Ads account lets you:

• manage one channel from one Google account
• manage multiple channels from one Google account
• use brand accounts to manage many YouTube channels at once or to manage multiple Google Accounts
• manage one channel from one Google account and let multiple people manage a channel

Correct answer is:

use brand accounts to manage many YouTube channels at once or to manage multiple Google Accounts

Explanation: You can link more than one AdWords account to your YouTube channel and vice versa. You can’t link a YouTube channel to AdWords if a channel has no public uploads and less than 10 subscribers.

Read more here: https://support.google.com/youtube/answer/3063482