Which adjustment could be best addressed with an automated rule?

A new ad group needs to be created with the settings from an existing ad group.
The maximum bid on a keyword needs to be adjusted when clickthroughs fall below .3 percent.
The budget for several ad groups needs to be increased by $200.
The maximum bid on an ad group needs to be adjusted on Sunday, May 22.

The correct answer is:

The maximum bid on a keyword needs to be adjusted when clickthroughs fall below .3 percent.